I had been having CEL issues since Mon.--could have been any or all of a half dozen things causing the truck to miss and run rough. Here's what I ended up doing. I had about a half a tank of gas, and dumped in a can of Chemtool B-12. I had used this before in a 4-wheeler that refused to start. I ran it a while, let it sit a couple of days, then started it again today. No missing, no vibration, and the check engine light went off. May not be a permanent fix, but it is running like it is supposed to. Thanks to all who responded to my woes.

 

When you get a chance, stop by any Advance Auto or other auto store that reads codes for free and see if their are any CEL codes stored. (Just curious.)

 

depending on the year, you dont need to go any where...the code will flash

 

To retrieve the code from a 96 you turn the key quickly(within 10sec) to, on, off, on, off, on. With it left on the last time, cel goes out, then it will start flashing 2 digit codes. It will always end with a code 55, that signifies end of codes. 12 is recent battery/pcm disconnect in last 50 starts. If that was the only code, it would go
Flash 1x, pause, flash 2x, longer pause, flash 5x, pause, flash 5x

Code meanings at the link below
http://www.allpar.com/fix/80s-codes.html