94 Pontiac engine in Sidekick!

[fixkick]

Hello: Mr.Zackman

its it misfiring? if yes, under what conditions
hot , cold engine or both?
idle, racing n neutral, or driving or only up hills or only accelerating?
G16a 8valve (u code? by gm)
are the flash codes running 12s? Diagmode jumper.

Dear Fixkixk:
You may recall that I was struggling with installation of an engine in my son's Suzuki a few months ago. Anyhow, I finished the job in February. and the car has been running since, but somewhat roughly. I tried to check every possible thing to improve the performance, but I cannot seem to improve it anymore.

Today, I checked the engine VIN (which is 2CGBJ18(U)XR6903914). The search states the engine belonged to a 1994 Pontiac Sunrunner!

The question I have is that whether the rough running issue might be due to incompatible ECUs? would that be an issue?

I should note that the car starts beautifully, on the first crank. The engine compression is also quite reasonable, a minimum of 155 psi in each cylinder.

Your expert input would be much appreciated!

Regards,
Zackman