hey guys i found out what was wrong with my 88lo3.the connector to your coil.check to see if it is loose or not .i took the car too a friend of mine that works at a chevy dealer here in town and we found it.the tabs on the connector wear with age and break. if these tabs are broken it makes the contact between the coil and the connector to be weak(the blasted thing almost wiggles off!!!)it will throw your idle way off,make you run rich and make your car run like crap.i don`t know if this will help everyone but my car runs like a champ now.so give it a look see and tell me if it works for u.if you guys need pics give me a holler i`ll post them.

 

glad you found the problem... my car did something similar one time but it was because i forgot to hook up the ground wire to the motor that hooks to the back of the head...

 

After much tinkering and worrying I found my coil to distrubutor wire was slightly loose. Only slightly. One cold day and my beloved wouldn't start because of that!!! I was shocked.