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My 3800 has recently developed a weird idle issue when warm, it will idle rough but when I remove the oil cap the idle smooths out. Bad pcv valve a possible cause?

92.1 or 92.2?

PCV is easy enough to check, pull it and see if it rattles. Only costs a few bucks if you want to replace it for good measure.

92.1, under acceleration it runs just fine and has plenty of power, it just idles rough.

Engine light? Codes?

neither, now the right front turn signal is burned out, lol.

Gotta love that car though. I think EVERY part on it, aside from the motor/trans has been replaced/repaired or fudged at one time or another.

Still daily drive it?

Edit: Have you checked all the vacuum lines and connections. I would think if that was the issue you would notice it when driving too, but its worth a shot.


Last time I pulled those lines off my 1997 they turned to dust. Yeah, that was fun trying to find replacements.

not lately I plan on it for winter tho.

94SilverSSEi wrote:92.1 or 92.2?

PCV is easy enough to check, pull it and see if it rattles. Only costs a few bucks if you want to replace it for good measure.

Replace both O-rings-the one around the PCV valve itself and the one that seals the chamber at the top. For that one, you'll need a 38MM by 4 MM O-ring. The local Ace hardware has them in the Dorman section. Also, make sure the MAP sensor doesn't leak and is correctly seated.

Based on my recent experiences, you should really replace all the vacuum lines.

Where is the map sensor on an L27?

I don't think there is a map sensor on any 3800 lol. Isnt the pcv integrated into the head and intake manifold? I know it is on my 93.

L36 Map is on top of the PCV area. Not sure about the L27 though, maybe doesn't have one?