engine runon

I have a 88 with a 2.5l. I rebuilt the motor last feb. when you turn the ignition off the engine continues to run a little bit. It kind of sputters. also the idle is not steady. its kind of rough and it goes up and down in RPM's.

i would start with checking the timing, it's called "dieseling" when the engine runs on like that. rough idle can be caused by timing, but i would also check your Idle Air Motor see if it's clean or not.

I replaced the idle air control valve. is there a way to calibrate it. I'm pretty sure the timming is set correct. If the distributor is a tooth off you would able to compensate by turning the distributor when you set the timming correct?

yes you are right about the timing.....and n you cannot tune the idle air motor, but i did think of something else you could do. You can get computers "flashed" now and all that does is updates the computer with new codes and fixes any issues that GM (or any other manufacturer) had with your truck, basically once they found problems arising they would set a code for it and update them accordingly....if you talk to your local parts store they should be able to hook you up, i think it invloves sending the computer out to ge it flashed, most places don't do it on site. hope that helped