Kinda long, so for those who are too lazy to read it all:

Short.....
Old LD9 died, replaced w/ rebuilt LD9. New motor has random misfire, car was diagnosed. Replaced spark boots/plugs, coils, & coil housing. Still having issues. Need suggestions/help. Owner is ready to shoot someone.

Long....
So, literally I’ve been pulling my hair out trying to diagnose and cure this problem. I recently replaced the original LD9 from my car as I spun bearing #1. So I have a new/rebuilt LD9 which was installed with no major issue(s). So after driving around for a couple of days, I noticed this “rocking” movement that the motor makes while at idle; say at a stop light for example, feels like a very rough idle. So I’m . With no CEL/SES light, I take the car in for diagnostics. Found stored code: P0300(multiple/random misfires). So I’m . The tech found evidence of spark leak from cylinders 1 & 4. The tech recommended I replace the top coil housing and spark boots. I replaced what was suggested and I also went further and replaced the coil packs and spark plugs. The plugs were torqued to 13-ft lbs and gapped to 0.050inch. Mind you, everything was replaced with all the overpriced GM OEM AC Delcro crap and the ****ing car does the same crap!!!
Someone suggested that I do a crankshaft relearn procedure as a new motor was installed and the ECM is calibrated for the old motor. Could this be a factor? According to my Haynes manual, it does say that if the crank position sensor is “repositioned”, it could cause a random misfire DTC and should get this procedure done. Well, the sensor wasn’t necessarily “repositioned” but it was transferred from one motor to another. I think it’s a good idea since I’ve done just about everything else, and it will cost ~$90.00.
Anyone have any suggestions on where to go? I have a new motor in the car and I can’t stand the fact that it’s running like a POS. Please help!

Car info:
2000 Grand Am
2.4/auto



H.O.N.D.A = Hold On Not Done Accelerating