97 Malibu 3.1 V6 Rough Idle

I have a 97 Malibu with the 3.1 V6 and it sometimes does not idle just right. It it usually hard to tell but sometimes in drive at an idle it seems to make the car shake just a little. It is NOT misfiring. I just tuned it up with new plugs and wires. I cleaned the throttle body and ran fuel injector cleaner in it. I have checked for vaccum leaks and can't find any. It runs great on the hwy and anything just above an idle. It actually runs fine at and idle but just does not settle down completly at and idle. Of course you can watch the engine move just a little at an idle also. NO check light and no codes so as you figure it is not very bad but just enough to be anoying. Does anyone have any ideas?
Rob

I have a 97 Malibu with the 3.1 V6 and it sometimes does not idle just right. It it usually hard to tell but sometimes in drive at an idle it seems to make the car shake just a little. It is NOT misfiring. I just tuned it up with new plugs and wires. I cleaned the throttle body and ran fuel injector cleaner in it. I have checked for vaccum leaks and can't find any. It runs great on the hwy and anything just above an idle. It actually runs fine at and idle but just does not settle down completly at and idle. Of course you can watch the engine move just a little at an idle also. NO check light and no codes so as you figure it is not very bad but just enough to be anoying. Does anyone have any ideas?
Rob
Is this something new?

It was doing that when I bought it so I don't know what is going on. Like I said...I have done all of the above already since I bought it.
Rob

I have a 97 Malibu with the 3.1 V6 and it sometimes does not idle just right. It it usually hard to tell but sometimes in drive at an idle it seems to make the car shake just a little. It is NOT misfiring. I just tuned it up with new plugs and wires. I cleaned the throttle body and ran fuel injector cleaner in it. I have checked for vaccum leaks and can't find any. It runs great on the hwy and anything just above an idle. It actually runs fine at and idle but just does not settle down completly at and idle. Of course you can watch the engine move just a little at an idle also. NO check light and no codes so as you figure it is not very bad but just enough to be anoying. Does anyone have any ideas?
Rob
I have a 98 malibu, 3.1 and i also bought the manuel ($15 bucks highly reccomend it!) It mentions an idler valve that when old or dirty could cause what your talking about, If its the problem, it would be very simple to install yourself. I also reccomend two bottle of Chevron brand fuel injection cleaner in the tank, Whatever Chevron uses it works.

I don't know what that idler valve is. I'll try to find it and check and clean it but I did clean the throttle body really good. It didn't help the problem. Also, I forgot to mention that it is sometimes a bit hard to start. It always does but sometimes take 2 or 3 tries to get it running.

Hey fritcr,

Sounds like the same thing I experienced. Nothing wrong with idle in park or neutral, just in drive. Here's a thread I started but I don't have an answer for you yet. If you figure out anything please let me know.
http://www.automotiveforums.com/vbulletin/showthread.php?t=461725
Kev.

It looks like this was posted a while ago, but for what it’s worth I’ll offer my experienced observations about rough idle with a Chevy 3.1 V6.

There are two smooth black plastic Positive Crankcase Ventilation tubes - one going from the front valve cover PCV port to a port in the upper intake manifold just after the throttle body, and another slightly thicker one going from the rear valve cover port to a rubber port in the throttle air intake.

Try putting some Ultra Black RTV on the PCV port on the rear valve cover behind the EGR valve, and on the PCV port on the intake manifold just behind the throttle body & let it cure overnight. This will seal those ports, because the ribbed grommets quickly get brittle & flatten out or fall to pieces entirely, creating a huge vacuum leak at the metal ports where each tube goes in.

Also, check your MAF sensor wire harness by wiggling it with the engine on idle. If the engine stumbles when you wiggle the wires, you need to replace it.

The only other thing I can think of is your idle air control solenoid. I would remove it & clean the port. A new IAC valve might be in order as well.

If your engine is also knocking at idle but not when driving it, it might be time to replace the knock sensor.

I had each of these issues & fixed them. I hope this helps.