OK, so here is the deal. I have owned many GMs with quad 4 engines and thought I knew all there little gremlins with head gaskets and pretty much anything above the cam cover. I had a chance to buy a 92 Achieva SCX W41 car from a guy at work that was fed up with it for $700. I smirked and thought to myself I would have this running by the end of the week and be laying rubber by him on the way out of the parking lot after work. He said he tried everything……..
Here are the symptoms. Car has constant miss. Sometimes it will run perfect when it is cold and soon start missing. That is the only thing that made me rule out mechanical issue like a down cylinder (did compression test and all good) or headgasket and thought it had to be fuel or fire. When missing I can unplug the #1 and #4 fuel injector and it does not affect the missing of the vehicle in any way, but if you do it to 2 and 3 it will immediately chug and die. I believe I had isolated it to fuel or spark on those cylinders.
He told me everything was replaced on top of the cam cover. He even had another ECM for the car. Instead of believing him I have some friends at the parts store and you usually can’t return electrical components but they will let me. So I bought new coils, coil housing, AC Delco plugs, and plug boots. Replaced all that with new……….no change, same miss. I raised the coil unit above the cam cover and loaded the boots with the old plugs and grounded them out on the cam cover and had someone turn it over and I had nice blue spark to every plug……scratch head…..I have good spark. I removed fuel rail with injectors still loaded in it and had someone turn over then engine…….all injectors sprayed. I don’t know if it was the best spray pattern but they were all consistent and should run the vehicle fine……..scratch head…..I have fuel. I have had problems with cats before but it didn’t affect idle only acceleration and this cat has been hollowed out.
OK ….uncle, uncle I scream to the quad 4 gods. Does anyone have any additional ideas as to what I am missing here? My pride will be ruined next week and crow will taste its worse ever when I admit defeat to the guy I bought this from.

Thanks in advance for any help!

I also spray a bit of throttle body cleaner in the intake to see if the engine with smooth out thinking that if it was fuel problem this would maybe feed the starved cylinders. It didn't help.

Not quad knowledgeable here but,I would start by checking the ohms off those two injectors.If they are not with in spec,buy new ones.If the miss was always cold/warm maybe timing,map sensor, but not likely with ur issue.However it prolly want help but,unhook the egr vacumm line see if it goes away.I would be checking those injectors and your fuel pressure(actual) from the schrader valve.Unless the injector harness for those two are not so good.Idk I am just trying to help and good luck.

well I would do all that ron love has suggested, and check you compression when the motor is upto temp(i know its hard and yeah its sucks ass your gonna get burnt on that stupid small area they give you to work on the plugs in, but it sounds like the cylinders loose compression at temp, wheather it be rings or valves, but with my knowlege of motors and the QUAD/LD series motors thats my best advice, good luck