Tural

maybe someone can chime in. i can't figure this out.
i took out the 63mm tb out of my '99, cleaned it, changed the tps and decided to see how it would perform in my bone stock '97.
the iac is different in 97 and 99, so i swapped the '97 iac to the '99 63mm tb and put it on my '97. it idled about 200rpm and it would die. when i give it gas, the throttle response is instant. but then it revs back down to 100-200rpm and dies in about 10 seconds.
so, i start thinking that one of the sensors is bad.
i take it off and put the stock tb back on the 97 and it runs fine.
i put the 63mm tb back on my '99 and that runs fine.
i didn't keep the 63mm tb on my 97 long. i didn't drive around.
i didn't reset the ecm.
i wonder if the ecm needed to adapt to the bigger tb... i'm out of ideas...

Phatwitaph

the ecm needs to be reset after any throttle body changes, so it can relearn. But I dont think thats the problem worth a shot tho.

Tural

i bolted the 63mm tb on my '99 and it worked fine from the first start.

Tural

iac was the culprit. the iac can act up without throwing a code. i made a mistake of dipping it in acetone because it was too dirty to clean by wiping. do not do that.
if you inspect your iac, just make sure that the pintle moves back and forth without much resistance. DO NOT overextend it. just move it in and out a little bit.