Service engine light comes on about 15 seconds after driving. Has a code 88. Engine seems to run fine.The truck is a 94 6.5turbo, auto trans, 1ton. Any ideas? Thanks

My 94 6.5L NA 2500 does that when the static timing is too far off for the IP to compensate for by adjusting TDCO. If it is a new code it could be a lot of issues related to the IP. I saw that last week when I replaced my IP and the static timing slipped after a day or two. I had to find a S-wrench to get the nuts tight.

Dan

Go thru the Diagnostics Checklist in STICKY's, 1ton, with particular emphasis on battery cables and grounding - might be your IP, tho you didn't list any mileage or particulars.

Could also be a recent load of bad fuel, or change of fuel type - what are you running?

The light came on after I had the new ip timed.

If you have a scanner I would look at your timing. If your TDCO gets too large you get the number 88 (I think on mine it was anywhere past 2.02).

Dan