You might want to use the "Search" next time, it's been brought up before on here I think.
Anyways, first of all, some people claim adjusting them will work (but not permenantly), this is a time consuming fix. You can also try a can of engine restore or valve medic. It made it go away on my 90 Coupe, but it comes back about 300-500miles or so. Engine restore is like $8-10. Valve Medic might be cheaper.
I'm sure more will reply, I think this is the most common thing on the G1 Engine.