high idle

[MoparN75]

I need suggestions. I recently replaced the engine in my '87 SC. It was converted to T2 years ago, and uses a CSX stage II LM. It ran fine prior to engine swap (old engine had wrist-pin noise). But now, it revs/idls at 2500rpm! I'm only getting code 31. I've tried 2 other throttlebodies, checked vacuum line multiple times, removed and tested and cleaned all solenoids, nothing seems to make a difference. The only way to bring the idle down is to either turn the distributor or unplug map sense vacuum supply which causes it to go pig rich. Any ideas?

[shackwrrr]

Did you use a 2 piece? If so check under the throttle body neck for a hole. This is the support brace hole and if left out it does that

[MoparN75]

That was it! Bracket was in place, but no bolt in manifold. Thank you!

[shackwrrr]

Had the same problem, chased it for a day and a half. Make sure you loctite it, had one fall out and cause problems too.

[MoparN75]

Wish I could say I only chased it a day and a half. Thanks, I used thread sealer on it, it should be okay.

[John B]

Dang. I wish my idle problem was that simple!