Jan 102017

1999 Mercury TracerI put new ignition coil in it, and still when there is humidity in the air or raining it will not run. Wont start in rain.

I have a 99 mercury tracer with 203,000 miles on it, just put a new ignition coil on it and new plugs and wires, but every time there is moisture in the air or it is raining, the car will not run, it starts just fine, but once I try to drive, it will not keep running. If it is dry out, it runs just fine, but not with moisture in air. Why will my car not run when there is moisture in the air?


Moisture or water is getting on part of an exposed portion of the ignition system. You have done the first best thing by replacing the spark plugs, wires and coil. Now that you know those components are not at fault try something different. Get a can of WD-40. The WD stands for Water Displacement. Pull the plug wires up and spray the boots with WD-40 and reinstall. Make sure there is no moisture around the spark plugs before installing.


Sometimes the technician will discover leaking valve cover seals around the spark plugs causing engine oil to accumulate in the spark plug wells. Your engine has a Distributorless Ignition System (DIS), so there’s no distributor cap or rotor. Once the spark plug wires and connections are known good, then you diagnose the coil pack and ignition module that controls the input to the coil pack. There are also crank and cam sensor inputs to your computer that could be failing. It costs money to properly troubleshoot these possibilities rather than just start replacing parts hoping to fix the problem. You may end up burning your starter motor up and causing other damage if you don’t get this fixed. Start by removing the spark plug wires at the spark plugs and see if there’s any engine oil on the boots. If so, fix that problem first.

Source: bobweb

Dec 162016

1994 Mercury TopazI bought my 1994 Mercury Topaz V4 Automatic about a month ago. Once I pulled the codes and it had a code P0158 for the MAF sensor. I replaced the MAF sensor, air filter, PCV, and fuel filter. When I was on the freeway today and I noticed it was making this exaggerated revving sound after 60 mph. Then it slowly and consistently lost speed. I immediately got off the freeway in time to coast into the gas station as it cut off. Then when I tried to restart it, it won’t turn over. Help!


Won’t Turn Over

The good news is I do not think the MAF sensor you installed has anything to do with the engine not turning over. The issue you described sounds like the alternator is no longer charging the battery and the engine ran off the battery for as long as it could and then quit. A dead battery is the most common reason for an engine not to turn over. However there are other possibilities. You’ll find a no start diagnostic chart to follow from this page.

Mercury Code P0158 – O2 Sensor Circuit High Voltage Bank 2 Sensor 2

P0158 Ford Description

The heated oxygen sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. An Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

Code P0158 Possible Causes

– Faulty Rear Heated Oxygen Sensor Bank 2
– Rear Heated Oxygen Sensor Bank 2 harness is open or shorted
– Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection
– Inappropriate fuel pressure
– Faulty fuel injectors
– Intake air leaks
– Exhaust gas leaks

Nov 242016

2001-Mercury Cougar2001 Mercury 6 cyl oil light flickers on and off. It has new oil and has done this since last yr. I went through the car wash and it stop flickering?


The engine oil light flickering is generally caused from a faulty oil pressure sending unit. The sending units tend to leak and cause pour connection to the attaching wires. Going through the car wash may have helped the connection for the time being. Ultimately I recommend replacing the oil pressure switch.

Oil Pressure Switch – Oil Light Flickering


NOTE: High output engine shown, base engine not equipped with oil cooler.

  1. Raise and support the vehicle.
  2. Disconnect the oil pressure switch electrical connector.
  3. Remove the oil pressure switch.

oil pressure switch location - oil light flickers

Nov 062016

2001 Mercury Grand MarquisMy alternator was grinding & needed to be replaced. Was on my way home to do just that & it died. Car had to be towed. Replaced the alternator, charged the battery & car would not start. It kind of made a small backfire sound or “poof” noise. I thought maybe the spark plugs got fouled, so I replaced those too. Charged the battery again & tried to restart the car. Nothing. It cranks, but does not seem to try & fire up? Checked the fuel pump reset in the trunk, but it was not tripped either. What else could be the issue? I need this car for work and any help is much appreciated. Thanks! My car has 120000 miles. My car has an automatic transmission.


The first thing to do would be to determine what it is not getting.

  • Spark
  • Fuel
  • Fuel injector pulse
  • Fuel pressure
Test for Spark

A quick test would be to spray starting fluid into the air filter and see if it wants to run on that. If it does, you know you have spark and some sort of fuel related issue.

Oct 102016

2002 Mercury SableWill oil stop leak stop an oil leak?


I would imagine the size of the leak and where it is leaking would play into it. But LUCAS makes an engine oil stop leak. It is formulated to renew worn seals with no risk of damage to the engine. The stop leak may be worth giving a try for small leaks. The price is right for a quick test. This additive complements the oil that is already in the engine. This make it nice so there is no need to drain any oil. Have read many great reviews on this product.

Aug 192016

2009 Mercury Grand MarquisNo door locks, not able to move mirror, no truck, not able to use outside touch pad, no dome light


Trunk fuse #2 7.5 amp feeds through the drivers door module and then to the trunk. Same Fuse is used for the mirrors. Same fuse is used for the Keyless entry pad and feeds the drivers door module.

So my educated guess would be to check the #2 fuse first.


Jul 132016

1997 Mercury Grand MarquisHave a master cylinder leak. Cant get the car our of park. Is there a safety or is it an unrelated issue?


Unrelated issue. The park brake shift interlock switch is electronic and the brakes are hydraulic. A leak in the hydraulics will not affect the brake interlock switch.

Shift Interlock System

The brake/shifter interlock system operates as follows:

  • All vehicles use a brake shift interlock mechanism consisting of a shift lock actuator (3Z719) attached to the steering column tube (3514).
  • This mechanism prevents shifting the transmission out of the PARK position unless the brake pedal (2455) is applied.
  • When ignition switch is turned to the RUN position, the shift lock actuator is energized, locking shifter in PARK position.
  • When brake pedal is applied and the stoplight switch (13480) is activated, the brake shift lock actuator is deactivated and the transmission range selector lever can be moved out of the PARK position.

Brake/Shift Interlock System Cleaning and Inspection

  1. Turn ignition switch to RUN.
  1. Verify that transmission range selector lever is in PARK.
  1. Without brake pedal applied, verify that transmission range selector lever cannot be shifted from PARK.
  1. Apply brake pedal. Verify that transmission range selector lever can be shifted from PARK.
  1. Shift transmission range selector lever to REVERSE.
  1. Verify that ignition switch cannot be turned to the LOCK position.
  1. Shift transmission range selector lever to PARK.
  1. Verify that ignition switch can be turned to the LOCK position.
  1. If shift-lock system is not operating as specified, refer to Diagnosis and Testing.
Mar 282016

2001 Mercury Cougar
My 2001 Mercury Cougar will turn over but will not start. The car had been parked for a while and before the fuel pump and filter was replaced. the car ran fine before parking it


Sometimes after your 2001 Mercury Cougar has been setting for a while it requires some extra TLC. The fuel system pressure may bleed off and may need to be primed. This is easily achieved by cycling the ignition key on and off 10 times, waiting 5 seconds in between each movement. This will build the necessary fuel pressure needed to fire the fuel injectors. Of course starting out with a fully charged battery is assumed.

2001 Mercury Cougar will not start

If the no start situation turns out to be more, further diagnosis will be required. You will need to figure out what the engine is not getting when trying to start it. Check for spark, fuel pressure and fuel injector pulse. A quick spray of starting fluid in the air filter would let you know if it has spark or use a tester.

Specialty Tools :

Spark Plug Tester

Fuel Pressure Test Kit

Fuel Injector Pulse Tester

Tests for injector pulse in car, just touch the tip to the side of the injector and crank the engine. A light flashes when injector pulses.

Jan 102016

2008 Mercury Mountaineerit died on me i try to start it engine turns fine head and rear lites do not work now and it will not start


You may want to start by checking the fuses and electrical connections at the battery. Usually the lights would still illuminate even if the engine would not start. The only common between the lights and power to the engine is the battery. We know the battery is good or the engine would not turn over.


Jan 022016

1999 Mercury Mountaineer
I have a 1999 Mercury Mountaineer 5.0L V8. It just recently began acting up. After warming up the engine goes through heavy power loss and inability to climb ANY hill. Usually cannot get above 30-35. I just recently replaced plugs and wires for a tune up and a faulty coil pack (approximately 5-6 weeks ago) causing a misfire on cylinder #8. Today in troubleshooting I attempted the “Backyard Mechanic” trick of unplugging the MAF sensor and took it down the road, no change at all in acceleration issues or on idle, truck runs the same. Unable to spot any exhaust or vacuum leaks or issues, recently cleaned MAF housing and changed Air Filter as well. All of these issues arose after a heavy ice storm, do not know if this had any impact or was just bad timing. I need help, any ideas??


I see you stated you cleaned the MAF sensor. More damage is done trying to clean the MAF sensor than good. However unplugging the Sensor should have kicked the check engine light on and forced the closed loop mode and run fine. Since it did not do this the next thing I would check would be the fuel supply. Check fuel pressure, etc. Might try power braking against a building while someone sprays a shot of starting fluid in the air filter to see if the engine revs or bogs.  If it revs, the engine is starving for fuel. If it bogs, then you know it is not starving for fuel. Move to checking the exhaust back pressure at the O2 sensor ports. 1 1/2 psi is normal, anything 3 psi or more is a restriction.

Back Pressure Tester

This back pressure tester can easily fit anywhere you need it to with its flexible hose. Less than $40 and includes free shipping. Follow the image for more Details…

  • Test for clogged or obstructed catalytic converters and mufflers
  • Threads into Oxygen Sensor Port
  • Kit includes 12MM and 18MM adapters to fit most domestic and imported vehicles

back pressure testback pressure tester