2003 S60 2.4T Rough idle when car is warmed up

mkevolvo · Post by **mkevolvo** » 31 Jan 2015, 09:58

I have this problem with my 2003 S60 2.4T. The car starts up fine and idles smooth when the vehicle is cold. Once the vehicle is warmed up, the idle is very rough...but the rpm remains at 700. I've replaced the plugs, coils, MAF, upper engine mount, transmission mount, and throttle body with no luck. I also checked the engine for vacuum leaks....nothing was found. I guess I'm stumped. Could this possibly be caused by the temp sensor? Camshaft sensor?

draser · Post by **draser** » 31 Jan 2015, 17:21

Can you check temp sensor, cold sensor will read over 1000 ohms, hot will read a few tens. I'd also do a parameter scan. Any codes? Camshaft pos sensor is fine.

mkevolvo · Post by **mkevolvo** » 31 Jan 2015, 18:00

No codes are coming up on the scanner. I'll check the temp sensor tomorrow (just got done replacing the front wheel bearing). I know another little quirk is when the car is in park and you rev the engine up to 2k and let off on the gas...the car will stumble a little when the needle drops down to 700.

quietcoolone · Post by **quietcoolone** » 01 Feb 2015, 14:32

mkevolvo wrote:No codes are coming up on the scanner. I'll check the temp sensor tomorrow (just got done replacing the front wheel bearing). I know another little quirk is when the car is in park and you rev the engine up to 2k and let off on the gas...the car will stumble a little when the needle drops down to 700.

Not sure how relative this might be to what i just went through on a 2002 S60 (not turbo), but for all its worth, check to see if there is pressure or vacuum in dip stick or remove oil filler cap -- (many recommend using a rubber glove). Or check for smoke from these two areas which would indicate PCV needing attention.

Post by **oragex** » 01 Feb 2015, 19:07

Does removing the dipstick and un-tighten the oil refill cap help the idle go better?