I have a 1995 Mercury Cougar XR-7, with a 4.6 Liter V-8, that has 157,000 miles on it. It has been regularly maintained. It is running awful and showing codes for Cylinder #1 misfire and Cylinder #5 misfire.
It has been to 2 Ford dealerships and been examined by 2 other experienced certified mechanics. It has left several people pulling at their hair, trying to figure it out.
1 Ford dealership mechanic couldn’t find an exact problem and suggested I replace the engine – I’m not ready to accept that answer.
The other Ford dealership mechanic said that it had a bad intake valve, so I had a scope ran in the cylinder and found no bad valves.
1 Certified mechanic said he ran every test he possibly could and could find nothing wrong with it and said that theoretically, the engine is in perfect order and should have no problem, that he could find and that he couldn’t help.
The other certified mechanic ran all the probes and even used a Sun machine on all the electrical leads and it came back in normal parameters and that he couldn’t determine the cause of the problem.
Here is a list of things that have been done to rule out problems:
1. Plugs and Wires
2. Cleaned EGR and EGR Passage
3. Swapped injectors and bought 1 new one
4. Changed Plenum and Intake gaskets
5. Changed Coil Packs
6. Changed Ignition Control Module
7. Changed the fuel filter
8. New Mass Air Flow and Air Flow Sensor/Switch
9. New Throttle Positioning Sensor
10. A Compression Check – Holds 178 to 180 psi in every cylinder.
11. Had voltage check on every injector and every sensor on the car by all 4 mechanics.
12. Checked fuel psi and it is within parameters.
13. All of the plugs get fire – Cylinder #1 plug is a little wet from fuel and cylinder #5 plug is a little black.
14. Checked cam lobes and they are good
15. The car ran fine – I shut it off at 11:00pm and the next morning I started it up and instantly had a cylinder #1 and #5 misfire.
16. While the engine is running, you can unplug either injector for Cylinder #1 or #5 and it still has the same miss.
Can a computer be causing the problem? Any ideas of where to go or what to do next? Any insight would be sincerely appreciated.
Thanks - Arron
have the same problem?
Monday, January 8th, 2007 AT 12:16 PM