Hi I just changed the engine of my b2300 1997 and since that, the engine idles rough when starting the truck, it goes up and down (between 2000-2500 approx.) then it idles fine but will die after about 2 minutes of idle. I tested my IAC and TPS with a multimeter and they seem to be in good condition, but when I unplug the IAC the truck runs better, no rough idle.

I changed the fuel filter and the spark plug cables.

Any idea of what it could be?

Thanks

 

Could be a bad IAC then, Have you tried cleaning it?
It may also be a MAF problem, i'd clean that too.

 

Yes I cleaned the IAC but it did'nt get better, will iac cleaner do the job to clean my MAF?

 

No, you need MAF cleaner, they're pretty sensative.

 

did you try resetting the computer?

it also sounds as if you might have a bad coolant temperature sensor, unless
the problem also occurs when the engine is warm?