Sometimes when I'm on the highway cruising at 70-80 mph in 5th, the car throws a brief SES, and the car runs like crap during that short SES. No codes. Does anyone have any ideas?

 

What exactly does it do when it "runs like crap"?

 

EGR valve

 

Pull the code and get back to us. It is a whole lot easier to diagnose when we know the code it is throwing.

 

As I said in my first post there are no codes. It happened to me again in the drive thru at wendy's today. SES light came on and it tried to stall. By running like crap I mean it sounds wierd and different and stalls if im not moving. I'm putting in a new O2 and switching to SD soon anyways so maybe it isn't a big deal. And a bad EGR means consistent stalling under light throttle, I had that on my caprice and it was a whole different animal.

 

Alright, it's finally giving a code.

51 for the ECM. Which is convenient because I already have all the parts I need to switch to SD.
Thanks guys.

 

It really went nuts on me on the freeway today, does anyone think it could be the fuel pump crapping out?

 

Code 51 should be a prom error. When it gave the SES light, that was probably the computer restarting after it locked up when it couldnt read the prom. Check to make sure the memcal or whatever your computer uses is securely seated and that the contacts are clean. Even slight corrosion can cause problems.

EDIT: didnt see the SD part.