foxbod90

the idles moves slowly up and down at idle. the tach doesnt move much but i can hear it outside the car. when i change gears like from park to drive it would bounce a bit for about 10 sec and then correct itself. what could it be? many new parts so i think could be vaccuum leak?

MustangBradley

Vacuum leaks could lead to what you are describing. Pull fault codes from the computer and see if your Idle Air Control valve or your TPS is showing a fault. If you don't have any codes, then a vacuum leak is probably it.