I have replaced the plugs,wires, cap and rotor, fuel filter all with ac parts, still runs rough, i did a fuel pressure check at the engine, all within specs. i have found coolent leak at the front of the intake manifold, not bad just damp, could this make it run bad? no water in oil, oh, after it warms up it runs ok and the engine light goes out. i have checked the egr and other sensors. I have been told it could be the coil or the spider etc etc. Heck in not buying all that crap unless i know really think it is the source of the prob. by the way this is a 99 Blazer. 4.3, thanks for any help guys/gals

 

If your intake gasket is bad it could be an issue. When it heats up metal expands, check the torque on the lower manifold bolts.

 

Thanks 4x4, i will give that a try