Chevrolet Repair: 1988 Silverado drives fine idles rough after warm - code 32, fordscorpio, cracked block

Question
I just rebuilt the motor in this truck due to a cracked block.  Used a block from a 1972 truck.  It runs fine cold, after running check engine light code 32 comes on -- then when slowing down to stop idles rough.  I have replaced the EGR valve along with numerous sensors.  Checked for leaks along the throttle body, but cannot find a leak.  Read to do an exhaust back pressure test, cannot find out how to do one.  What do you think?

Answer
Hi Jo,
Here are a couple great links for starters.

http://www.fordscorpio.co.uk/cleanmaf.htm

http://www.chevytalk.org/threads/showthreaded.php?Cat=0&Number=1366279

If that doesn't help, go to this site and browse around.

http://www.chevytalk.org/


Van