Ok, I just acquired this '94 2.2L Sonoma from my daughter in law, and can't believe how bad it ran. I got it home and checked it out. It has 167K on it, and they had just replaced both coil packs, wires and plugs. However, it was only running on 3. Compression check was good on 3 cylinders, but one was probably a low, but shouldn't cause this problem. I noticed that the #4 cylinder plug still looked brand new, like it had never fired, even though it was. I pulled the injectors and #4 was faulty. I cleaned and checked the other 3 the best I could, and am satisfied they're working, and replaced #4 with a new one. The engine runs decent, but I got insurance, drove it on the road today to get the emission check, and noticed it misfires under 'no load' condition, but runs good at idle and under heavy load. It's smooth as silk under a load, which just seems backwards. It even has lots of power under a load with the throttle open. Has anyone run across this, or have any ideas. This problem seems to be just back aswards as to what normally happens. It's not setting any codes, and as rough as it was running, it even PASSED emissions check. Thanks for any ideas.
