1993 Oldsmobile Achieva

Engine Performance problem
1993 Oldsmobile Achieva 6 cyl Front Wheel Drive Automatic 157600 miles

I have a 93 Olds Achieva SC, I just replaced the catalytic converter and fuel filter, and a tune up. When the transmission is in park the engine seems to run fine. Once I place it into gear the engine starts running ruff, as if it is misfiring. Also when in drive the vehicle seems to not have any get up and go power. After placing it back into park or neutral the engine startes surging the RPMs and sometime turns off. I have run the self diagnostics and come with code 28, which from my understand is the transmission. The cruise control doesn't even work. I can't tell if the problem is the engine or the ECM.
December 8, 2008.

Hi: I tried looking up information for you on a code 28. Everything I found delt with quad circuit problems. However, after following the steps for diagnosing the problem, everything ended with " Make sure PCM connections are clean and tight.&Quot; So as of now, that is what I recommend.

Let me know what you find, and I'm sorry I can't copy and paste from the online manual we use or I would show you the process that is listed.


I finally figured out what was causing the problem and what code 28 stands for.

The problem was with one of the coil packs on the electronic ignition control moduel. After making several calls I found out how to test them.
- with both wires of one coil pack at a time. Start the engine and look for arcing across the two terminal posts. If it does not arc then the coil is bad. The Coil can still fire a plug, but not with enough juice to create a good spark.

The code 28 refers to the abs system onboard. On of the wheel sensor sences a wheel spinning at a different speed than the rest of the wheels.

Dec 22, 2008.