My car has been giving me that stupid SES light I havent pulled the codes yet (it would help solve my problems I know) but from what I have read I think it might be the EGR, this is whats been going on:

Car has rough idle, especially on cold mornings, even in the afternoon when its warmer its still rough (sounds really cool like I gotta cam.....but I don't, so that is a problem then)

After driving around and the car gets up to operating temp the SES light comes on.

When stopped at a light the car idles fine but the SES light is still there

The car seems to be running fine I have been driving a lot with the SES light on and the car does fine on the highway but that stupid light is a distraction.

Just gave the car a tune up and changed the O2 sensor thinking that was the problem

If anyone can verify that it is or isnt the EGR that would be cool, just looking to see what kinda trouble its going to be

Oh yeah do I have Positive or Negative EGR back pressure valve?

Thanks
Jason

 

Pull the codes.

None of us can do that for you.

 

Yes, pull the codes! Put a paper clip or wire with both ends slpiced open into the ALDL unit to terminals A and B They should be the two terminals on the top right side under the dash. Do a search on ALDL. I'm sure you will find out how. Let us know what the results are! It's always good to hear results. I was runing a code 32 which is an egr and having the same symptoms you are having. Turns out, my egr sonlenoid was bad.

 

Greek,

The code causing the constant MIL probably is NOT from an EGR fault - probably. The only time the EGR is commanded open is at part-throttle cruise under low loads, like cruising along at 45MPH+. It should not remain on at idle.

Take five minutes and retrieve your error codes:

Form a paper clip or short piece of wire into a "U" shaped jumper.

With the engine and ignition turned off, locate the ALDL connector under the dash, in the driver's foot well area. It should be just to the right of the steering wheel on Firebirds, and on the left side on Camaros. There should be a small rectangular cover over the access hole in the lower dash trim.



Insert a tool as described above (paper clip) into the 'A' and 'B' terminals on the ALDL connector:



WITHOUT STARTING the engine, turn the ignition to the "RUN" position. Watch the Malfunction Indicator Lamp (MIL) - it will begin to flash. This is also commonly called the "Service Engine Soon" or "SES" lamp. The first code will flash three times, and will usually be a code '12'. This is encoded by one flash of the lamp, a brief pause, then two successive flashes of the lamp. Each code will repeat three times, so you should see a "Code 12" flash three times. Any other error codes will follow in numerical order, and each code should flash three times. After all codes have been displayed three times, the "Code 12" will again flash three times, then all other codes will follow as described earlier. This cycle will continue until the jumper is removed or the ignition is turned off.

After you have made a note of all error codes, turn off the ignition and remove the jumper immediately. If you forget to remove the jumper and attempt to start the engine with it in place, you could damage the ECM. For this reason you should remove it immediately.

Once you have a note of all error codes, check this file for the decoding:

GM Error Codes.pdf.

(You'll need Adobe Acrobat Reader to view/print the file.)

 

Thanks for the instructions, worked perfectly.

I pulled a Code 25- MAT(manifold air temperature sensor) Sensor High Temperature fault

What does this mean?
Also when I started it up this morning the idle was really rough once again and black/brown smoke was coming out of the tailpipes.

Thanks
Jason

 

IAT = Intake Air Temp sensor

High resistance = what it does when it's cold
Low resistance = what it does when it's hot

If the wire is disconnected, it thinks it's like -67° out or something, so it extremely richens the mixture. If it's shorted to grond (dangling against the block, or the wire pinched in something), it will think it's about 250° out. Either way it's got the ECM in a state of majoe confusion.

Find the sensor, it's somewhere in the intake air tract before the throttle, most likely its wire is unplugged, plug it back in, life will be good.

 

The wires to the IAT sensor were bare so I guess that they were grounding out or something. Now I know why my car was acting funny. Just need to replace those wires and everything will be fine.........hopefully.

Thanks for the help guys