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View Full Version : Rough idle, stalling, reduced power


04v70
08-08-2009, 09:56 PM
I have conducted extensive search here and made repair attempts without success.
2004 v70 2.5t

Last night after returning home, I pulled in driveway and I noticed rough idle while in park. After a few moments of acceration in park, CEL came on. I shut engine and went in for the night.

Today I scanned codes with OBD scannder which has been helpful in the past, however no codes detected.

Symptoms are rough idle while in park. Engine very jumpy, CEL on.

After searching forum, I installed new MAF and checked all coil packs with no luck. I also unplugged battery for a while and no change.

Any indication on what the problem might be?

Recent maintenance: TB, Serp Belt, New PCV system, clean throttle body and replace gasket, new radiator.

I have noticed the throttle body is humming quietly after engine turned off and key removed. Don't remember if it always did.

Please help if you can, thanks!

-Rob
ecbsykes
08-08-2009, 10:00 PM
If the CEL is on, your scanner should pull a code...

Sometimes a faulty Engine Coolant Temp sensor will cause screwy stuff like this.
MoeB
08-09-2009, 05:08 AM
I was thinking dirty throttle body due to clogged PCV system until I saw you just had it all cleaned and replaced. It sure sounds like a TB issue, though.
sjonnie
08-09-2009, 06:06 AM
Symptoms are rough idle while in park. Engine very jumpy, CEL on.

Recent maintenance: TB, Serp Belt, New PCV system, clean throttle body and replace gasket, new radiator.


Sounds like a vacuum leak. Check all hoses, listen around, do propane test etc. If you can, get a measure of the short term fuel trim (STFT), if it is high (+8 or greater) you surely have a vacuum leak. Check all the vacuum hoses, including those to the turbo boost control valve, intake hoses and all PCV hoses. If the CEL is on then there is a code.
04v70
08-09-2009, 06:59 AM
Is the turbo control valve right above the turbo behind the block??
sjonnie
08-09-2009, 07:26 AM
The turbo boost pressure control valve is actually mounted on the side of the air intake. It has 3 hoses going to it marked with red, yellow and green.
04v70
08-10-2009, 09:31 AM
OK, my car went to VIDA equipped Volvo indy this morning. I will report back when I know more.
sjonnie
08-19-2009, 08:50 AM
Anything to report?