Idle drops when gas pedal released

[curtisr]

Hmm, I did search this but I didn't have any luck...(my ignorance I'm sure).

My '87 924s starts fine and has no trouble maintaining a steady idle of about 950 rpm; however, after revving the engine and releasing the gas pedal the tach falls to about 900 and then goes back to 950.

Is this symptomatic of a vacuum leak or is it something else? All suggestions greatly appreciated.

[flash75]

Sounds normal to me.

Clifton

[alfadoc]

Perfectly normal for Bosch injected cars with the "barn door" airflow meter. You let your foot off the gas, the flap in the airflow meter snaps shut, and it takes a second for the idle air bypass to take over.

[curtisr]

Whew! Thanks everyone!!!

[Dave Colangelo]

Ill take "What is, slow to respond engine control systems from the 80's" for $500


Regards
Dave