Dec 202016

Chevy tahoeRecently the engine service light came up with code P0300 multiple misfires. I used timing light to pin point which cylinder wasn’t firing and came up with #4 and #8. So I checked wire for resistance and plugs seemed to be fine. In addition I replaced both coils and I still have multiple misfires on #4 and #8. my next step would be?


Chevy Code P0300 – Cylinder Misfire Detected Random Cylinders

The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Therefore , start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leak are found the next step is to replace the spark plugs. In conclusion if the problem persist more tests needs to be done to diagnose problem, proceed to “Possible Causes”.

P0300 Possible causes

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

There is a factory Technical Service Bulletin on this Vehicle for Code P0300: TSB#03-06-030F

Dec 182016



Adjust Idle

Beginning in 1985, some engines were available with a throttle body fuel injection system. And all engines were fuel injected starting in the 1986 model year. By 1992 a central multi-port fuel injected engine became available as well. All fuel injected engines are controlled by a computer. This computer regulates idle speeds. It also supplies the correct amount of fuel during all engine operating conditions. No periodic adjustments are necessary or possible. Therefore there are no adjustments to be made.

When the idle is high, check for a vacuum leak. If it is low try cleaning the throat of the throttle body and check your air filter. When the idle seems to be stuck, clean or replace the IAC – Idle Air Control valve.

IAC Replacement

1.Disconnect the negative battery cable.
2.Disengage the electrical connector from the idle air control valve.
3.Loosen and remove the threaded IAC control valve and gasket using either a 1 1 ⁄ 4 in. (32mm) wrench, J-33031, or equivalent.
To install:

Before installing a new idle air control valve, measure the distance that the valve extends (from the motor housing to the end of the cone); the distance should be no greater than 1 1 ⁄ 8 in. (28mm). If it is extended too far, damage may occur to the valve when it is installed.

4.Measure the valve pintle extension. To retract the pintle on a NEW valve, use firm thumb pressure and, if necessary, rock the pintle with a slight side-to-side motion. BUT, if reinstalling a used valve on which the pintle is extended further than specification, an IAC tester MUST be used to electrically retract the pintle.
NOTE: Do not attempt to physically retract a pintle on an IAC valve that has been in service, the force may damage the pintle threads. The force required to retract the pintle is only safe on NEW IAC valves.

5.Install the IAC valve and gasket to the throttle body and tighten to 13 ft. lbs (18 Nm).
6.Engage the valve electrical connector.
7.Connect the negative battery cable.
8.Reset the IAC valve pintle: A.There are 2 possible methods to resetting the IAC valve. First, depress the accelerator pedal slightly, then start and run the engine for 5 seconds. Shut the engine OFF for 10 seconds, then restart it and check for proper idle operation. If this does not work, start and run the engine until it reaches normal operating temperature. Drive the vehicle and the IAC valve will reset once vehicle speed is above 35 mph.


Dec 182016

1999 Chevy CavalierI have checked the fuel line, fuel filter and fuel pump on my Cavalier. They are all working. I broke down an waited for a couple of hours an it started up. I waited on the tow truck still got it home the next day went out an it wont start.


You will need to determine what the vehicle is not getting. The engine may not be getting fuel injector pulse, spark or both. I have a wonderful chart that goes over the step by steps for diagnosing a no start situation.

Cavalier No Start

Dec 142016

Chevy El CaminoHeadlights don’t work. Have parking lights, markers and tail lights but no headlights. Initial issue was very dim headlights, but now no lights at all.


Headlights Don’t Work

My first thought would be a bad connection of some kind. It may be from some corrosion or rust, brittle wiring or loose connection. I will provide a wiring diagram for reference. Check for power at the light switch coming in and going out when the switch is pulled. No power to the switch, check the fuse and wiring between the fuse and the switch. Once that checks good move to the headlights. Check for good ground and then for power when switch is pulled. Repair as needed. Of course all testing should be done with a fully charged battery.

Headlights Wiring Diagram 1984 Chevy El Camino

headlights don't work wiring diagram 1984 Chevy El Camino


Dec 122016

Chevy TahoeWater coming out the muffler not tailpipe. Over heating radiator stop up. I put a new thermostat on it.


Perform Diagnostics

If the radiator is stopped up, it would be a good idea to install a new one. Therefore it may also be a good idea to flush the entire cooling system too. But first of all rule out the possibility of a blown head gasket because water coming from the muffler isn’t normal.


Dec 082016

1998 Chevy SilveradoExperiencing a miss in engine at idle and at speed it misses and sounds like popcorn popping in the muffler. — Replaced plugs and wires, distributor cap and rotor, finally replaced entire distributor. “NOT FIXED”… Replaced Fuel injection spider. “NOT FIXED”…Help Please!!!


Enhanced Ignition System Description

The ignition system initiates combustion by providing a spark to ignite the compressed air and fuel mixture at the correct time. In order to provide an improved engine performance, fuel economy, and control of exhaust emissions, the control module controls the distributor spark advance, or timing, with the ignition control (IC) system.

The ignition system uses a primary and secondary sub system in order to accomplish the timed spark distribution. The primary system consists of a low voltage trigger device which determines the base timing. This signal is modified by the ignition control driver (ICD) module. The signal travels to either or both the engine and transmission processor, or control module, for base timing reference. Another signal is sent back to the ignition control driver (ICD) module, which has been adjusted by the control module, advanced or retarded, in order to trigger the coil, according to the requirements of the engine.

The secondary system consists of the ignition coil which has primary (low voltage) windings and secondary (high voltage) windings. The secondary side of the ignition coil generates a high voltage which high tension spark plug wires deliver to the spark plugs.

The control module controller now controls the ignition control (IC) and bypass functions.

In order to properly control the ignition or combustion timing, the control module needs to know the following things:

System Operation

 The enhanced ignition system used on all OBD II engines somewhat resembles the current distributor ignition (DI) system described in the Ignition Systems. However, the system has been greatly enhanced in order to make it compatible with the new OBD II regulations. The enhanced ignition system provides a spark at precisely the correct time in order to ignite the air and fuel mixture for optimum performance and fuel economy. The system consists of the following components:
  • Vehicle control module (VCM)
  • Distributor
  • Ignition coil driver module
  • Ignition coil
  • Crankshaft position (CKP) sensor

This system does not use the ignition module used on the DI systems in the past. The VCM controller now controls the ignition control (IC) and bypass functions.

The crankshaft sensor, located in the front engine cover, is perpendicular to a target wheel attached to the crankshaft. The target wheel is equipped with slots situated 60 degrees apart. As the crankshaft rotates, the target wheel rotates past the crankshaft position sensor. The rising and falling edges created by the slots cause a signal to be sent back to the VCM. This signal occurs three times per crankshaft revolution and is referred to as the 3x signal for V6 applications. The signal occurs four times per crankshaft revolution and is referred to as the 4x signal for V8 applications.

The VCM then utilizes this 3x (V6) or 4x (V8) signal in order to provide the correct spark to the engine by way of the single coil driver module. The single coil driver module is basically an electronic switch that when commanded by the VCM, causes the primary coil voltage to breakdown, energizing the secondary coil and providing a spark via the coil wire to the distributor cap. The distributor consists of the following components:

  • Cap and rotor
  • Camshaft position sensor
  • Gear drive and shaft

The camshaft drives the distributor shaft which rotates providing a spark to the correct cylinder by way of the cap and rotor. The camshaft position (CMP) sensor functions much like the crankshaft sensor previously described but provides only a 1x signal to the VCM. That is, for every 2 rotations of the crankshaft, there is 1 rotation of the camshaft. Note that the camshaft position sensor will not affect driveability. The sole purpose of the camshaft position sensor is to provide the VCM with the necessary information for the misfire diagnostic trouble codes (DTCs).

Nov 242016

2002 Chevy TruckBrake problems: New pads, rotors, master cylinder and booster, 4 big jugs of new fluid… pedal to the floor right after starting and sometimes very, VERY hard pedal with no breaking. 19″ of vacuum at idle then fluctuates between 13″ after throttle let off to 23″ on reeve.


Did you bench bleed the master cylinder before installation? Did you bleed the brake system to get all the air out? It sounds like you did not if the pedal is going to the floor. Pumping the brake pedal will get you a hard pedal and no braking if there is air in the system. Air in the system is the most common issue with brake problems after the system has been open.

Brake pedal feel is firm, but brakes lack sufficient stopping power or fade

  1. Check the operation of the brake booster and brake booster check valve. Replace worn or failed parts.
  2. Check brake linings and brake surface areas for glazing and replace worn or damaged parts.
  3. Check for seized hydraulic parts and linkages, and clean or replace as needed.

Source: Brakes

Nov 202016

2004 Chevy CavilierHow much would it cost in total to replace the shift cable?


About $60 for the part plus the part mark up. Then about 2 hours labor at shop rate.

  • Cable(part+markup) = $100
  • Labor(shop rate x hours) = $200
  • misc(because they can) =$15
  • Total = $315
  • Tax (local tax 7%) =$22.05
  • Grand Total = $337.05 Shop Estimate

Do it yourself Estimate: Part = $60

Shift Cable - 2004 Chevy Cavilier

Shift Cable Replacement Labor Estimate

Shift Control Cable Assembly, Replace

Labor Times
Comments Factory Regular Severe
1.3 1.8 2.0

How to Replace Shift Cable


Shift Control Cable Adjustment

  • Set the parking brake.
  • Remove the console.
  • Lift and unlock the cable retainers.
  • Push the shifter neutral lock clip. Move the shifter slightly in order to center the lock clip.
  • Ensure that the transmission is in neutral.
  • Press and lock the cable retainers.
  • Pull the shifter neutral lock clip to its original position.
  • Install the console.
Nov 142016

2011 Chevy MalibuThere is some kind of leak on the passenger side of the car. The carpet is always wet. What can this be?


The most common reason for the passenger floor to be wet is a leaking heater core. Check your coolant level to see if it is getting low. Another reason, that is not so common, would be if the HVAC box drain is clogged. This would be from the air conditioning system running. If you don’t see it drip on the ground when the air conditioning has been running for a while than this could be the reason. Simple unplug the the drain with a pencil or screw driver.