New member here, first time Honda owner, and looking for some help!

Just changed engine with same year model, easy swap. Now new motor will not idle down, idle steadily surges from 1400-2000 rpm in neutral or Park. In gear it idles at 1100 steady, and it drives out good with plenty of power. Swapped old throttle body assembly with no change. Checked all vacuum lines and intake for leaks, but nothing there. It will eventually throw a code P0507 if left to bounce between 1400-2000, and idle re-learn doesn't do anything for it.

Does any body have any ideas???

 

i have same prob w/o engin swap just started last week.

 

Did you do or have any maintenance done before it started? Looking at the possibility of a bad computer, but don't know how to confirm that yet. Thanks for the feedback and I'll keep you posted of any fixes.