anyone help me out on an idleing problem?

If anyone could give me some ideas id really appreciate it. My car starts fine and accelerates great, never had any problems there, but it idles hard or shakes when its in park or stopped in drive. I replaced the pcv valve, timing chain, fuel filter, air filter and dumped numerous bottles of fuel injector cleaner into the gas tank but nothing seemed to help. the car has 135k miles.

thanks alot,
kyle

Check the engine and transmission mounts.

The 3800 naturally shakes due (in part) to firing order and other factors. Most likely your rear tranny mount is worn out.

Do you know how to check the mounts?

Albertj

Im not sure how to check the rear tranny mount. Is there a good way to do so?

You could also check for a bad fuel injector - one that doesn't close all the way or one that doesn't work right at low openings could still let it drive okay but idle rough -

At idle, go around one at a time and unplug each fuel injector. With one fuel injector unplugged, see if the idle gets worse, then plug it back in and do the next one. When you unplug one that makes no difference to your already poor idle you've found a bad injector.

There's a little metal wire lock across each plug, I used needle nose pliers to pull the wire back. That wire locks the connector onto the injector.

Drerk has a *great* point. I'd do that first; wish I'd thought of it.

As for those mounts... there are pictures of the mounts on this site but I don't remember where. Basically to see the rear tranny mount, put the car on ramps, crawl under, and look for it behind/below transaxle at frame rail. You are looking for torn/cracked rubber. The rubber parts of these mounts are kind of light.

Albertj

The timing chain? Surely that was not for this problem. Obvious problems are a vacuum leak: look closely at every rubber hose under the hood. Wiggle them to make sure they aren't cracked and leaking. And the traditional spark plugs and wires, they can cause a bad idle. Spray the throttle body with gumout and clean with a soft rag. Could be a lump of carbon in the EGR valve, had that happen in a 4.3L engine- if it accelerates great but idles bad I'd look for a vacuum leak or EGR.

TAKE OUT THE MAF BEFORE YOU SPRAY ANY HARSH CLEANER IN THERE.