Occasionally I would get the SES on steady on startup and it would die w/o help from the accelerator. Then, after driving for a short it would go out and all was well again. I've pulled for stored codes and found none.

Mon. I was traveling under curize at 65mph for a few hours when suddenly the SES came on and she felt like power dropped off a little. Soon I could feel the power fluctualte a little and then the SES was out and back to normal.

Several times thereafter I could feel power drop off and soon come back to normal though no SES on every such fluctuation.

This one has me stumped as I can't imagine what would cause the intermittant SES along with slight power loss without any codes??

I've thought about hooking up my AutoXray and taking a drive till it acts up again to see if the ECM is seeing anything unusual but thought I'd try this knowledge base first.

Any input would be much appreciated.

 

Are you scanning for current, or history codes?

If the SES light is coming on, but the ECM isn't storing a trouble code, it could be the ECM itself that is having the problem.

 

To date I have only scanned the ECM for stored codes after returning home.

The possibility of a bad ECM was one thought that crossed my mind but it would have to be an intermittant as I can plug in the scanner and monitor ECM parameters with no problem during "normal" behavior.