Alero 2000 -- SEO light/Trac Off/car shudders

Since January, my Oldsmobile Alero has been going through periods where it starts to shudder during acceleration (with little power), the Service Engine Soon light and Trac Off lights come on; the ABS light does not come on. Eventually, it would start running smoothly again – around the time I take it to the mechanic. This time, however, it hasn’t stopped.

The mechanic has over the course of several visits replaced the spark plugs, the ignition coil, and the ignition module assembly. As I drove home from the mechanic today, it started again.

The engine not only stutters, it seems to go through phases where it is fine and surges forward then starts shuddering, and loses power, worse when I have the fan running.

Any help, ideas?

It sounds like there’s a voltage drop to the vehicles electricals causing the control modules to go crazy. And the first thing to have checked out is the positive battery terminal at the battery.

Your vehicle has the GM side mount type battery terminals. The postive terminal has a red plastic/rubber cover. Under this cover is where corrosion can form causing a voltage drop to the vehicles electricals.

Have your mechanic remove the positive battery terminal from the battery, and then peel back the red cover to expose the terminal connectors. If a lot of corrosion is found under this cover, replace the positive battery cable assembly.


Thank you for the FAST reply! I will have my mechanic look at that. I took a look myself. Although everything “looks” fine, I noticed that in the tray under the battery on the positive side, there is a dried yellow substance. As if something wet filled up, then dried, leaving behind that yellow stuff. Since it’s only on the positive side, I think you may be onto something. Unfortunately, this weekend is a holiday weekend, so it may have to wait until Monday.

Thank you again! I will post again when I know more.

The positive battery terminal is fine. No residue or corrosion at all. Any ideas where else I should check?