Engine Check Light

[90plow]

Truck: 95 GMC 1500 4wheel drive auto TBI 305 v8. Well it all started about a week ago exactly. Last saturday I was pulling out of a driveway at school and it was icy so i backed up threw it in 4 wheel and barely made it out slipping all over. Take it out of fourwheel in the street while in drive (which it says your allowed to do). Then I'm going down the road stop at stop sign go to pull out truck jsut about dies then lurches back to life almost as if it had misfired, look at the dash CHECK ENGINE light is on %$*#. So I pull over shut down several times tryin to restart it. Get to where Im going in limp mode or with the motor acting funny when givin gas. Shut it off put in Neutral shift from 2 to n on T-case and then restart, light is off WOW great grand. I start the truck next morning go somewhere no problems park it for a week no problems drive to my house no problems. Get home go to work put it in 4 wheel no problems. Start it back up pull out put it in 2 wheel drive while its in N and sitting still. Get to end of road go to pull out same thing, truck dies off then goes like its bogging or missfiring. Now it takes some time and a few tries to get the light to go off. Fine works all day go out tonite come out 2 hours later start truck let it sit talk to my friends bla bla for like 5-6 minutes. I get in the truck check engine light is on son of..... so this time i thought it wasn't going off took me about 8 tries to get it off. I have no idea what is going on. I put a chip in the truck over a year ago so I dont think that is it because I dont normally have these problems. I just changed the oil yesterday thats not it. I can't figure what is going on. Please help. I sprayed down all the throttle control linkages tonite with PB blaster to see if that might have been sticking, but I just don't know enough to figure what is linked to the problem.
Sorry for the long post.
Thanks in advance,
Eric :confused:

[BRL]

It needs to go to a shop that can put it on the scanner & it will tell them why its coming on. At least that's what I do when it comes on. There are so many different reasons the light can come on that it's not worth trying to figure out by trial & error IMO.

[JohnnyU]

Take a paperclip and jump the terminals A & B of the diag. connector. They will be the ones in next to each other in the upper lright corner of the connector. Do this, then turn the key to the on position, engine not running.

The SES light will flash once, pause, then flash twice. That is the start/end code. If there is a fault code stored in the computer, it will flash after the "12" has flashed three times. Record the numbers that are flashed, then post them, I have a book and I'm sure Wyldman will too, and will beat me to posting it ;)