2002 S80 2.9LSmall Jerk In Engine When In Idle

divinedavis · Post by **divinedavis** » 14 Jun 2014, 14:34

I've recently changed the PCV Valve Oil Trap (FCPEuro.com) which stopped the whine. It stopped the RPM fluctuations also. When I'm in park or when I'm in drive and I have the car idling it seems to have a small jerk once every two seconds. I have 138,000 miles on the car. The lights would dim a little every time the car would find itself jerking.

Just had the oil changed (which I regret i didn't do myself).
I changed the spark plugs.
The fuel injectors are clean with no gunk.
I cleaned the throttle body.
The MAF looks pretty damn clean too.

Post by **Oly_850** » 18 Jun 2014, 06:55

Are you getting a Check Engine Light and are there any codes? At first blush this sounds like an intermittent misfire P0300.

divinedavis · Post by **divinedavis** » 18 Jun 2014, 08:28

No more check engine light. I just get a small jerk when I idle & when I turn on the AC.

Post by **rmmagow** » 18 Jun 2014, 10:55

Are you sure it isn't just the A/C kicking in? Leave the A/C off for a while and see if jerking stops.

divinedavis · Post by **divinedavis** » 18 Jun 2014, 12:36

It still happens, but not as much.

Post by **Oly_850** » 18 Jun 2014, 12:39

Is it regular and does it vary with RPM? Do you have to have the A/C on to make it happen, and do RPMs fluctuate?

Worse when the car is cold?

divinedavis · Post by **divinedavis** » 18 Jun 2014, 13:31

It's regular. The RPM does not fluctuate anymore. It stays at about 700-1200. When the A/C is on it still doesnt fluctuate. Just a small jerk, feels like something stops for a millisecond.

divinedavis · Post by **divinedavis** » 18 Jun 2014, 13:40

The car has just started these problems so i dont know if it's worse in the cold.

Post by **Oly_850** » 18 Jun 2014, 16:02

I think your got a coil over pack that is:

1) not grounded well ( booted down tight, two harness connections clean & tight)
2) arcing to the head through a torn boot
3) just weak, has yellow dim spark

OR

Your cam position sensor on the rear camshaft on the drivers side is not giving you a consistent ignition trigger.

Either way, any of these conditions should light up a MIL lamp.

Have you had the codes read lately?

divinedavis · Post by **divinedavis** » 18 Jun 2014, 19:57

Where do I have to go or what do I have to get to get codes read? & THANKS!