Bourbon powered V8
Join Date: Sep 2002
Location: Canberra, Australia.
Re: Engine Problem - Please Help
Sound slike similar problems I had in my EF. I also took it to (two) Ford dealers, and they could not diagnose the problem as the ECU was not getting any errors back. This was explained as the ECU is getting a signal - it's just the signal wasn't really good.
From what you describe, I think it could be one of two things - the Idle Speed Control (ISC) valve, or the Oxygen (O2) sensor.
Try the O2 sensor first - the fact that you have extractors suggests this may be the cause, as the O2 sensor is further away from the exhaust side of the head than it was with the standard manifold. To help in the diagnosis of this, disconnect the O2 sensor first (there is a clip near the exhaust headers on the drivers side, sort of down near the steering rack/chassis). Take the car for a spin around the block - it may run rich, but if it runs better than before, then you know it's the O2 sensor and the car has been running too lean.
If that doesn't make any difference, time to look at the ISC valve. To diagnose the ISC valve is a bit harder. Try start the car and let it idle, then (with the car running) disconnect the plug. If there is no difference, then the ISC could be your trouble. Try cleaning the ISC valve on the throttle body (there are thread around on how to do this). If cleaning doesn't work, try borrowing one off another car, or just replace it with a new one.
ISC valve is around $160 from Ford, O2 sensor (4 wire type) is around $100 from any auto shop - repco, autopro and Ford as well (I guess) etc.
If not's not either of those two things, then I don't know what it could be.
Note: I am not a mechanic, but I do a fair bit of my own car maintenance. Anything I have learnt has been learnt by trial and error, so I am just passing on the things I did, and the results I found.
AU1 XR8 Auto 147.9 rwkw (approx 215 fwkw)
AU2 Wagon HAD Auto
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FPV-XR Club ACT