I've read countless threads and spent countless hours trying to figure this out. Went from a no start to a start with terrible idle to now an engine that will stay running and is driveable but still won't idle smoothly. Replaced (Not by me but confirmed)
distributor, icm, plugs, coil and wires
tps, map, o2 fuel pump and cat

also seapped IAC with known good unit with no change. Engine has 118k and ran great before a jackass decided to rip the ignition out of it. I have checked all wires and everything seems good, have good fuel pressure and NO vac leaks. Vac lines are in proper routing order, when revving or revs decent doesn't studder or stumble but engine still has a slight visible shake to it just as it does at idle. Also no codes.
Have voltage at all injectors. I'm wondering maybe ECT, maybe a bad egr gasket, hell I really don't know I'm stumped. I just refuse to throw parts at something without at least a hint on reason behind it. Any help will be appreciated I need a smog last week lol thanks

 

its gonna be tough getting in there, but what does a compression check say?

 

Giant doesn't even sound believable but please bear with me. Here's the VERY VERY condensed version.... This ordeal started over a burned out interior dome light. Had a self proclaimed close to expert level "mechanic" come to fix the light and somehow the jackass Ends up in the engine bay (I do realize there is a fuse box there). One thing leads to another and now the poor mans wallet is over $1000 lighter and the E has an entirely new ignition/fuel/sensor system. But prior to te genius putting his hands on anything the damn engine ran like a top, passed CA smog with almost all zeros across the board. I haven't checked compression because the engine never ran again until I was recommended to the owner to come in and undo the horror scene. What the guy essentially ended up doing was shorting out the sig rtn circuit and frying that circuit in pcm which took me a week straight to diagnose. So anywho, I just don't see the need to frustrate myself trying to weasel in there to check compression; would everyone concur? It's so hard to believe I almost didn't want to post the truth. I have the damn thing just about licked (fires without hardly hearing a starter motor spin, idles up at first start and slowly comes down as it should, idle is very consistent albeit a bit rough, does not try to choke out and die at all, CEL has turned itself off without any resets or clearings, can be driven normally).
I'm going to double check the plug gaps again (.044) even though I have heard some sources say .52-.56. How much could a slightly mis gapped plug really cause on one of these EFI systems? I'm using copper auto 25s.
One new thing I noticed today when I had it running and used a plastic with rubber coating handled screwdriver to touch the boot on #3 plug the shock absolutely pushed me out of the cab so got a new wire for install tomorrow. I cannot see any arcing though in pitch black and I'm not gonna pull wires while running and risk that shock again to see if there is any change. When I pull a wire and start stop and repeat I get no discernible difference in engine vibration or sound

 

well I had a consistent rough idle and it was a bad wire on new wires with ceramic insulators so its possible. could be the plug is open too. If you are on 25's, I am using Pt 25s (AP25?)

back when SBDS was available, there was a test for cylinder balance where it checked the "crank angle word" which basically measured the time at idle between PiP pulses in milliseconds and found weak cylinders...Im pretty sure no existent tester can do that so you have to hit and miss plugs wires and injectors.

one thing to do is aim the raytek at the suspected cylinder and it should show about 75-100* cooler once warmed up at idle if its missing