Car Idles Awful in Drive, Ok in Park

[miyagi-san]

When my Tercel is in drive and I'm stopped, my car runs like absolute crap. It's even worse in 4wd. I touch the gas, and it's fine, but idling makes me think it's going to die. Weird thing is, I put the car in park, and it clears up. Any ideas where to start looking?

[terkill]

Hmmmmm

Vacuum leak?
or
Worn engine mounts?

[Neu]

Usually a vacuum leak somewhere.

We had a dodge that wouldn't go into 4wd, but when it did it would almost die, if you revved the crap out of it it'd stay going until you let off the gas. it was a vacuum line going to the transfer case.

[takza]

First thing is to increase the idle speed...hard to find idle screw under the air cleaner on the pass side.