What do you have your timing set at? Just did a GT40P swap on my 87GT MAF converted and Im at 10* and it barely idles, have to feather the gas. Have zero trouble codes either
See the "Surging Idle Checklist for help with all your idle/stall problems. The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes] for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.
well did u pull the spout connector when u timmed ur car?
alot of people forget to do that when they set there timming
and wounder why there car runs like crap
if u did that than
advance it to 14*
cuz stock is 10 but 14 is a nice lil spark advance