94 Pontiac engine in Sidekick!

[Zackman]

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

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Dear Fixkick:
No, there is no backfiring, or bad codes. It just sounds rough. I also think the engine is burning oil. It just sounds very rough running, and does not feel the same way it was before changing the engine.

I checked the eBay yesterday, and according to sellers of ECUs, the ECU of 94 Sunrunner is the same one that in 91 Sidekick (apparently).

So, I am conclude that the engine is just tired and not very good. What amazes me is the compression reading I got, which does not match what I am seeing in terms of engine performance!
Regards,
Zackman

PS. The oil idiot light comes on after the engine gets warmed up. I have bought a oil pressure gage that I will install today. FYI, I paid more ($20) to get the proper union from BSPT to NPT that I paid for the gage and the three unions that came with the gage ($15) - absurd!)