Hi! I have a 1991 Chevy Corsica, 4 cylinder - 113000 miles, and i have a 'Service Engine Soon' problem : I checked the car and it has an error 34. I have replaced my ECM three weeks ago, i just replaced MAP sensor and oxygen sensor but my car still does the same problem, even more frequently. The car runs smooth on a neat road, but any shaking induced by the road (like holes in pavement or a higher portion of road) makes the engine to stop for a few seconds (1-5) ... the Service Engine Soon light appears and the engine continues to run and after a while the light disappears sometimes, if the SES light stays on i observed that if i turn off the engine and then turn it on the light disappears. Sometimes the light appears and the engine stops while waiting at a stop. I don't know what's wrong with it. Please help!

Hi there
I would like to know if you've had the problem solve and how?? I have the exact same probleme?? Can you help??

Thanks
rej

I did a car check at MIDAS and they told me that the problem is the ECM. I had my mechanic change the ECM and I had no more problems like that. Now it runs very good.

Thanks

I had the ecm replace and it works fine now. I was told by my mechanic that there was small water leak that reach my my ecm and that was the source of the problem.

thanks rej

did you try changing the egr valve cuz that happen to mine and thats what i had to change.

I had the same problem and the answer was in a bad contact to the computer on the passanger side

A common problem when these cars get older is that water will leak into the ECM thru the wiring harness that runs from engine compartment thru the firewall. I sealed around the harness with some RTV silicone and have not had any problems. (200K)