Engine Problem - Please Help - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Mattnic2 · 10-13-2003, 17:18

I have an AU Series 3 XR6 and recently the enging has been running rough. I first changed all the plugs to Iridium, Changed the leads to Bosch Super Sports Conductice Core, K & N Air Filter and tried some Injector cleaner, but none of this worked. I then took my car down to my local Ford Dealer and they changed the fuel filter, did a flow/pressure test on the injectors, rebuilt the diff???, put in a new tail shaft??? and the engine still runs rough. When the aircon is on it's not too bad, but when it's off that's when it runs like shit. Also when i start my car up i'll let it idle for a minute or so and as i drive off, the car flatspots and it feels like it doesn't wanna go. I also have extractors if that helps narrow down the problem, and it's also a manual.

Please Help...

Regards

Matthew

JC-XR8 · 10-13-2003, 19:00

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.

Mattnic2 · 10-13-2003, 20:11

Thank you i'll give tht a try and let u know how i go...

mongrelEB · 10-15-2003, 04:01

If she flatspots you could also try running a multimeter over the TPS and MAP sensor.
Is it overfueling?

TopGhia · 10-15-2003, 11:47

Clean the MAF sensor. Plenty of threads here on how to do it.

cheers

galapogos01 · 10-15-2003, 15:30

Its a six! no MAF!

rossi · 10-15-2003, 16:41

I agree with JC. But I would lean more to the O2 sensors.

Did you put the extractors on, or was it like that when you bought it? Has it ever run sweet? Usually things go wrong after you modify something.

My two cents. Let us know how you go!

JC-XR8 · 10-17-2003, 06:57

Quote:

Originally Posted by rossi

Usually things go wrong after you modify something

Don't tell Laminge that (or HOTDBZ, or EBXR8240 or....you get the idea)

Quote:

Originally Posted by rossi

Let us know how you go!

What he said

Mattnic2 · 10-18-2003, 22:04

I changed the O2 Sensor and it runs almost perfect, it still misfires every now and again. And yes I had the extractors put on after i got the car.

Matthew

JC-XR8 · 10-19-2003, 03:03

So the O2 fixed most of it, but not all? I reckon you should check spark plug leads - especially number 3 and 4. Pull the lead off the spark plug and check the colour of both the lead tip and plug end - if either the tip or the plug is black at all, the leads need replacing. You may also find some grey/black residue on the outside of the lead, where it goes across the rocker cover - this means the leads are arcing. (I have had this problem on my car).

Ford/Motorcraft ones are around $90 per set plus fitting. You should be able to get a set of Topgun 8mm (you can also go 9mm or 10mm if you want, but it is added expense) for around $60-$70, and it only takes about 1.5hrs to replace them yourself (it is a bugger of a job!).