I have a 1992 Chevy 1500 with the 5.7L Tbi in it. I recently had to replace my head gaskets and now have have a rough idle. It seems to idle ok when im in park but when i go to drive or reverse the truck will start to shake and idle pretty rough. As soon as i give it a little gas it levels off, idle comes up to about where it should be. Anyone have any clue what it could be?

 

O2 sensor
Check for codes

 

i dont have a check engine light on, and last time i checked there were no codes. when im at at stop in drive when it idles it almost sounds like a lope or like it has a bigger cam in it, which it doesnt.

 

May be a vacuum leak.

 

yea thats kind of what i was thinking...i havent looked over all the vacuum lines yet. also i plan to put vacuum to my EGR to make sure it is working because i was told that could cause it too.

 

I had the same trouble I even replaced the spark plugs, fuel filter and spark plug cables.
It turned out to be my distributor cap