Oct 162019

2000 Chevy 2500

When my truck idles their is no whine. When my truck warms up and i drive it for a little bit and I stop at a red light or a stop sign and then accelerate that is when the whine starts. It also makes the accelerator vibrate just a little. I have a hydrobooster leak which causes the power steering fluid level to go down. I also have an issue with my 4×4. I have no lights on the indicator and no service 4 wheel drive message either. The indicator has been replaced along with the TCCM. Fuses have been replaced. I got told a sensor but what sensor and where would it be?

Whine Noise

The whine is from the power steering system having air in it. This will continue as long as the leak is not taken care of. The worst case scenario would involve replacing the power steering pump itself.

No 4×4 Indicator Lights

The most likely sensor that would be involved would be the selector switch. There is a chance that the wiring is the issue. Use the wiring diagram below for reference.

Automatic Transfer Case Select Switch Wiring Diagram




Oct 162019


Need help diagnosing lean condition, poor acceleration. Have had two shops try to fix with no luck. Did some parts shot gunning myself but still no change.

In 1986 almost all manufacturers decided to go with excessive vacuum controls on the engine. The most common cause of a lean condition is related to a vacuum leak. With this engine having so many vacuum lines I would start there first and then consider the intake gasket may also be leaking due to age. Lastly check the fuel injectors. There is a technical service bulletin out that concerns the fuel injectors becoming clogged and causing a lean condition and a lack of power.

TSB# 03-06-04-030F


Oct 162019

2007 Chevy Impala

I hit a super pothole in the street, it has done something to the electric system in the car. when my car door is open, all of my panel gauges work correctly. When I close my door  none of the gauges work and a message pops up constantly telling me my door is open. It also drains my battery in a couple hours. What could be the cause of this and how do I fix it ?

Certainly has to do with the electrical system. Most likely an issue with the door jam button. But may not be limited to just that. In fact it is quite common for the wiring harness that runs between the door and the body to develop an issue. This is in part do to the fact that the drivers door gets opened and closed more often then the other doors. Add in some age on top of that and the wiring becomes brittle.

First look at the wiring harness near the door jam for damage. Next look for shorted and open wiring. Since everything seems to work when the door is open you will need to wiggle the wiring during testing to get the best results.

Oct 092019

2011 Chevy Traverse

I recently replaced the ECM in my Traverse. It was driving and running good. I went to give it gas to pull a mountain and it went into a lower gear and would not shift out. By the time I got to the top of the mountain it was running hot. After it cooled off, I started it and headed home. After driving about 4 miles it died again (not hot) and now it will not start. I can turn the key over and it sounds like a car with a dead battery trying to start. My battery amp goes to 0 and the lights dim, but the battery is brand new. What could be causing my problems?? I’m scared to death the engine is locked up

It is possible that the alternator is failing to charge the new battery. Or the alternator belt came off. You would have lost power steering if that was the case though. I would start off by fully charging the battery and checking the battery cable connections. If you are hearing a bunch of clicks (click, click, click, click) when trying to start the engine, that would indicate a weak battery. One HARD Click would indicate a faulty starter. No Noise at all would indicate dead battery or loose connections or bad starter relay. In any case we have developed a step by step chart to assist in diagnosing a no start condition.

Oct 052019

2007 GMC Sierra

Engine burning oil

This question is in regard to a 2006 GMC Sierra 2500HD (8.1L gas engine) with 197,000 miles on it. It had around 60k or 70k miles when I bought it in 2012. It has had a rough life since then – lots of hauling and towing. It has had a long-running problem of burning oil (I would have to add some oil every month), but the oil-burning has suddenly gotten much worse, and I am adding oil every few days.

Every mechanic I’ve ever taken the truck to always says “that’s just what old trucks do, they burn oil”. Another problem (which I assume is related) is that the spark plugs get ruined frequently and have to be changed. I’ve had to change them at 124k miles, 130k (wires only), 170k, 183k, and 197k. At 197k, I told the mechanic I was tired of spending so much on spark plugs, and we decided to try a cheaper plug and see what happens. This, in addition to a full tune-up/fluid exchanges, fixed the symptoms I was seeing (intermittent shudder when idling, ‘check engine’ light coming on when going uphill over 45mph, engine misfire code P0300).

But then I only made it 1200 miles before those same symptoms returned. Same P0300 code, one ruined spark plug, cylinder 2. A mechanic replaced that one plug, and I made it another 80 miles before things went south again yesterday. This time it’s 2 plugs, cylinder 2 and another cylinder (he didn’t tell me which one). So we’re replacing all plugs with the better double platinum ones.

Any ideas what is going on? Am I just doomed to replace the plugs every 15k miles from now on? I love this truck and don’t want to get rid of it. For anyone interested, there are more details below, in case they provide any additional clues. Thanks in advance!

Full Maintenance History

  • oil changes are done every 5k miles
  • oil cooler lines replaced in 2013
  • major tune-up at 124k miles (transmission flush, coolant flush, 4×4 service (front/rear differentials, transfer case), spark plugs, fuel induction system service, air filter replaced)
  • 130k, replaced spark plug wires, cleaned mass air flow sensor
  • 132k, replaced fuel pump assembly
  • 169k, code P0171, cleaned mass air flow sensor
  • 170k, replaced spark plugs, plug wires (mechanic said plugs were really bad and covered in oil)
  • 174k, replaced air filter
  • 183k, replaced spark plugs and air filter
  • 1955xx miles, replaced serpentine belt, belt tensioner, and fan clutch; mechanic said spark plugs are misfiring/worn out (but I couldn’t afford to replace them yet); mechanic said “we took off the valve covers and looked inside of the cylinder heads, in case the valves are gummed up. But we didn’t really find anything except the piston rings are a bit burned out.” He recommended trying Lucas oil stabilizer and Lucas fuel cleaner (which I did) and using premium gas and higher quality synthetic oil from now on (which I did). He said the engine is burning lean, so better fuel will help that. Told me to get a tune-up as soon as I can.
  • at 197k, ‘check engine’ light came on every time going uphill over 45mph; code was P0300 (engine misfire; no other codes); idle is very rough; replaced spark plugs/wires with cheaper copper plugs as an experiment, did fuel exchanges (differentials, transfer case, transmission (& filter), coolant, power steering fluid); cleaned the air filter
  • 1200 miles later, replaced 1 spark plug; added “Engine Restorer 8-Cylinder” to the oil, as recommended by the mechanic
  • 80 miles later (today), replacing all spark plugs with the right kind. Mechanic says it will take a while of driving at high speeds for the “Engine Restorer” to work?

I travel a lot, so I rarely get to use the same mechanic. Whenever I go to a new mechanic, they usually tell me that my last mechanic was BS-ing me and/or didn’t know what he was talking about. I’m a car dummy, so I have to just take the word of these mechanics, and I never really know when I’m getting the run-around.

Thanks to anyone who made it this far in my post!
(attached photo is the cheapo copper spark plug after 1200 miles)

Oil Fouled Spark Plug

Print a copy of your history and present it to your next mechanic, they will appreciate knowing what you have already gone through.

Chevy engines burn oil. This is true but they shouldn’t foul the plug in 1200 miles. You have something else going on.

Definitely fouling the spark plug. So the engine is going to store the P0300 – Engine Misfire code when this happens. That is normal during this situation. There are several things that can cause this code and situation.  The good news would be that you have tried a few things that tell us which cylinders are the problem cylinder.

Compression Test

The next thing to do would be to have a compression test performed. This information can sometimes explain a lot of whats going on. And this will confirm the problem cylinder/s.

Head Gasket

If two cylinders next to each other are significantly lower than the rest there is a possibility of a blown head gasket. However a blown head gasket would also be followed by white exhaust smoke and coolant loss. Since you didn’t mention any of those symptoms we will move on.

Fuel Injector

If there is specifically one cylinder that keeps fouling out the spark plug there is a chance of the fuel injector being stuck OPEN(ON). When this occurs the cylinder rings will wash out(unseat) and foul out that spark plug. After time the the excessive fuel being dumped into the cylinder with washed out rings will allow the fuel to seep into the crankcase and contaminate the engines oil. When this happens you will notice excessive exhaust smoke and start fouling out additional spark plugs.

When looking at the oil on the dipstick it may also have a fuel smell. A quick test can be to remove the spark plugs from the effected cylinders and cycle the fuel pump on and off a few times. While keeping at a distance to prevent fuel from shooting out at you, look to see if the cylinder fills with fuel. If you find the fuel injector is stuck open you will need to replace it and and then perform an oil change to remove any contaminates oil.

Hole or Crack in Piston

You didn’t mention it but i want to cover engine ping. If you experience the engine pinging when climbing a hill or under heavy acceleration you may have caused internal damage. Continually driving the vehicle under these conditions will burn a hole in the piston. If this is the case you will have 0 compression and oil foul the spark plug quickly.

Worn Valve Guides and seals

When the valve seals or guides are worn you will see a puff of smoke at start up. Sometimes lasting until the engine reaches operating temperature. This usually occurs after the vehicle has had time to set and the oil drains down past the guide seals and into the cylinders.

Engine Misfire Causes

  • Faulty spark plug (s)
  • Faulty ignition coil (s) – Engine Coil
  • Ignition coils harness is open or shorted
  • Ignition coils poor electrical connection
  • Clogged or faulty fuel injectors
  • Injectors harness is open or shorted
  • Injectors poor electrical connection
  • Improper spark plugs
  • Insufficient cylinders compression
  • Incorrect fuel pressure
  • Intake air leak

Source: https://www.freeautomechanic.com/engine-misfire.html

Oct 032019

Chevy Malibu

I drive a 2009 Chevy Malibu. While driving it sometimes feels like when you push the gas pedal it doesn’t want to gain speed. Finally you’ll feel a shift and it’ll start to climb speed. Sometimes it won’t accelerate over 50 and when it does my traction control light comes on and esc warning. Any ideas on how to fix this?

  • If the RPM are climbing higher and not moving the car accordingly then it would appear the transmission is slipping. How high does the RPM go without moving the car significantly? If the problem is transmission related, the cheapest/easiest thing to try would be to add a little transmission fluid if it is low.
  • Perhaps the Catalytic converter is plugged. It’s been known to happen.

Source: Drunken Elvis

  • If one of the cats is plugged, usually you can tell by letting the car idle for 20-30 minutes. The plugged cat should be very hot, they will even get hot enough to glow red in the dark if they run long enough. You could try checking it after a long drive, see if one is noticeably hotter. (Use an infra red temperature gun for testing temperature of converter, do not touch)

Source: SBUBandit

Sep 292019

Chevy Cobalt

Can I program a new transmission control module myself?

Having the right equipment and knowledge to use it would be all that is required to perform the procedure.

Trans Control Module Relearn

Refer to Figure below when performing following procedure.

The transmission control module (TCM) must be programmed with the proper software/calibrations. Ensure that the following conditions exist in order to prepare for TCM programming: The battery is fully charged, the ignition switch is in the RUN position, the Techline equipment cable connection at the data link connector (DLC) is secure.

1. Program TCM using latest software matching vehicle. Refer to up-to-date Techline equipment user instructions.

2. Ensure that TCM connection is OK.

3. Inspect Techline equipment for latest software version.

4. Attempt to program TCM. If TCM still cannot be programmed properly, replace TCM.

Aug 272019

Chevy Aveo

Car will start up and just idle. Tried driving it around the block and barely made it. What causes this and how do I fix it?

First off, any existing computer codes should be pulled with the use of a scan tool. Next, post any and all existing codes in the comments. We can use these trouble codes to help determine what is going on.

Reset Limp Mode

One thing you will want to try is disconnecting the battery for a few minutes. Then reconnect the battery and restart the engine. This should reset the computer if it just happened to be a glitch.

Limp Mode

Under certain conditions, the fueling system will turn OFF the fuel injectors for a period of time. This is referred to as fuel cut-off. Fuel cut-off is used in order to improve traction, save fuel, improve emissions, and protect the vehicle under certain extreme or abusive conditions.

In case of a major internal problem, the ECM may be able to use a back-up fuel strategy for limp mode that will run the engine until service can be performed.

Chevy Aveo Tech Tip

Aug 122019

1997 Chevy Blazer

Tried to smog my truck didn’t pass so I did a tune up. Replaced plugs, o2 sensor and was replacing the distributor cap and rotor when I noticed the distributor was broke. So I replaced it. When I got it all back together it ran fine but coded a crankshaft positioning sensor. So I replaced that and it is still coding the crankshaft positioning sensor. I don’t know what to do now.

Chevy Code P0336 – Crankshaft Position (CKP) Sensor Performance

Chevy Code P0366 Description

The Crankshaft Position (CKP) sensor sends a reference signal to the Vehicle Control Module (VCM) in order to indicate the crankshaft position and the RPM so that the VCM can determine when to pulse the ignition coil, the fuel injectors, and the control ignition timing. This is a type D DTC.

Conditions for Setting the DTC

  • The Crankshaft Position sensor signal is missing for at least 0.5 seconds.
  • Engine cranking and the VCM receives 4 or more Camshaft Position signals without a Crankshaft Position sensor signal.

Action Taken When Code P0336 Sets

The VCM stores the DTC in History if the VCM detects an intermittent problem.

Conditions for Clearing the MIL/DTC

A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

Diagnostic Aids

A poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation may cause an intermittent.

Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Check for the following conditions:

  • Backed out terminals
  • Improper mating
  • Broken locks
  • Improperly formed or damaged terminals
  • Poor terminal to wiring connections or
  • Physical damage to the wiring harness

Refer to Intermittent Conditions .

How to Test Crankshaft Sensor Code P0366

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if the VCM is receiving the Crankshaft Position sensor pulses.
  1. This step checks the ignition feed circuit to the Crankshaft Position sensor.
  1. This step checks the Crankshaft Position sensor low circuit.
  1. This step checks the Crankshaft Position Sensor.
Step Action Value(s) Yes No

Important: Before clearing the DTCs, use the scan tool to record the Freeze Frame and the Failure Records for reference. This data will be lost when the Clear Info function is used.

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

Go to Step 2 Go to Powertrain On Board Diagnostic (OBD) System Check
2 Does the vehicle start and continue to run? Go to Diagnostic Aids Go to Step 3
  1. Disconnect the Crankshaft Position (CKP) sensor.
  2. Connect a test light to ground.
  3. Turn the ignition ON.
  4. Probe the Crankshaft Position sensor ignition feed circuit at the engine side of the CKP sensor harness connector.

Is the test light ON?

Go to Step 4 Go to Step 6

Connect the test light between the CKP sensor ignition feed and the CKP sensor Low circuit.

Is the test light ON?

Go to Step 5 Go to Step 7
  1. Turn off the ignition.
  2. Install the gray jumpers from the connector Tester Kit J 35616 between the engine harness connector and the CKP sensor ignition feed and ground circuits.
  3. Install a DVM set to the duty cycle position (select the AC volt position then press the Hz button twice to display % duty cycle) between the CKP sensor (3x) signal circuit (sensor side) and the CKP sensor Low circuit.
  4. Crank the engine.

Is the duty cycle within the specified range?

40%-60% Go to Step 8 Go to Step 9

Repair the open or short to ground in the CKP sensor ignition feed circuit. Refer to Wiring Repairs in Engine Electrical.

Is the action complete?

Go to Step 13

Check the CKP sensor Low circuit for an open.

Was the problem found?

Go to Step 11 Go to Step 12

Check for an open or short to ground in the CKP sensor (3X) signal circuit.

Was a problem found?

Go to Step 11 Go to Step 12
  1. Remove the crankshaft position sensor.
  2. Inspect the crankshaft position sensor reluctor wheel for damage replace if necessary (Refer to Engine Mechanical).

Is the reluctor wheel damaged?

Go to Step 13 Go to Step 10

Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement .

Is the action complete?

Go to Step 13

Repair as necessary.

Is the action complete?

Go to Step 13

Replace the VCM.


Important: If the VCM is faulty, reprogram the VCM. Refer to VCM Replacement/Programming .

Is the action complete?

Go to Step 13
  1. Using the scan tool, select DTC, Clear Info.
  2. Start engine and idle at normal operating temperature.
  3. Select DTC Specific, then enter the DTC number which was set.
  4. Operate vehicle within the conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic ran and passed?

Go to Step 14 Go to Step 2

Using the scan tool, select Capture Info and Review Info.

Are any DTCs displayed that have not been diagnosed?

Go to the applicable DTC table System OK
Aug 042019

2005 Chevy Silverado

I removed the instrument cluster off of my pickup dash and bumped the 4 wheel drive button. And now it is stuck in 4 wheel drive low. What can I do to get it back into 2 wheel drive ? I’ve already sent the cluster in to be repaired. I didn’t realize that it was in 4 Wheel drive Low until after I had already sent the cluster in to be repaired. Please Help !!


To disengage the 4 wheel drive you first need to be in neutral. The press the button to 4 wheel high or 2 wheel high or Automatic if equipped. Sometime it is helpful to back up 10 feet and then place the transmission into neutral.