[AliveGV]

I have a 2004 V6 2.5 Grand Vitara that has a possible fuel management problem. At steady throttle between 2000 to 3000 RPM will drop revs to around idle speed running very roughly then pick up again. This happens both while driving or stationary. Has new oxygen sensors, TPS, tried a second hand MAF, new plugs, tried coils, fuel pressure has been checked and all wiring/ connectors checked. No errors are coming up on a scan tool. Wondering if the ECU is the problem but hard to find 2nd hand and expensive new. Only thing I have done is fit extractors but problem developed some months after doing this. Hoping someone on this forum may be able to help.

[foolishme83]

dirty fuel?

[Built4thrashing]

Where are the Oxy sensors in the Exhaust? How far back?

Have you checked / replaced the fuel filter?

How many Kms it done.

[murcod]

The camshaft position sensor seems to fail on them a bit and go intermittent. Perhaps the extra heat from the extractors has caused it to fail?

[Rhinoman]

Is the scan tool capable of live data? if so what do your fuel trims look like?

[kenn]

Might sound funny but check the earth lead at the back of the intake manifold/ plenum somewhere at the top, to the body. I vaugly remember something like that with mine but I could be wrong. At least it's easy.

[AliveGV]

Thanks for the replies. Because fuel pressure is good I think Fuel filter should be Ok, isn't located in the tank.Oxy sensors are in same position as originals and vehicle done 140000ks. Scan tool is showing fuel trims going lean when problem occurs but it will be one bank then the other so not consistant. I am trying to get hold of a 2nd hand DIS to try and the earth has been cleaned up. Any more help would be great. Cheers

[murcod]

kenn wrote:

Might sound funny but check the earth lead at the back of the intake manifold/ plenum somewhere at the top, to the body. I vaugly remember something like that with mine but I could be wrong. At least it's easy.

That sounds like the same earth lead on our XL-7 that went. The connector plug in the middle of it looked like it had been in a toaster- all crispy and melted! I'm guessing a bit of current flows through it and there was some resistance in the connection. It didn't cause any driving issues in my case, I just happened to notice it one day when checking fluids in the engine bay.

PS: AliveGV - do you have your own Suzuki scan tool ? My '04 XL-7 isn't OBDII compliant, so I assume your 04 GV wouldn't be either?