Dropping Idle Speed
Thread Starter
Racer
Joined: Jul 2004
Posts: 278
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From: Tallahassee FLorida
Dropping Idle Speed
I have a 97 A4. My idle will drop below 600 RPM, and sometimes below 500. I will also hear a slight knocking sound somewhere in the drivetrain, and cannot pinpoint where, but it is happens with the drop in RPM (not every time, but sometimes). Will not drop below 600 with the air conditioning on, and stays constant. I have done the alternator and idler pulley upgrade. What could be the problem? Help me out fellas-
Race Director
Joined: Feb 2004
Posts: 11,651
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From: HOW FAST WAS I GOING OFFICER? Los Angeles Hating GM Dealership Service Dept.'s Since Sept. 2004
St. Jude Donor '04-'05-'06-'07
Sound like an electrical gremlin to me. Have you monitored you voltage? Is it constant? I can only tell you I had similar symptoms and I found a loose wire connection. Later, it turned out to be a short circuiting PCM (stealership trolls dropped a power wire on it). Electrical is a PITA to trace.
My advise would be watch your voltage meter on the DIC.
Try to isolate when this "clicking" occurs. In my case, I heard the clicking, opened the hood and finally observed the hood light flickering ever time there was a click. Also the voltage fluctuated. Since all the "short circuits" got corrected, all is well.
Dave
My advise would be watch your voltage meter on the DIC.
Try to isolate when this "clicking" occurs. In my case, I heard the clicking, opened the hood and finally observed the hood light flickering ever time there was a click. Also the voltage fluctuated. Since all the "short circuits" got corrected, all is well.
Dave
Race Director
Joined: Jun 2000
Posts: 13,733
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From: Hurst, TX USA
500 is about right for an A4 in gear. My CE would occationally drop down to 2-300 and start to stall. But I never found out what the problems was. If you always stay at or above 500 I wouldn't worry about a little fluctuation. No clue on the knocking, though.
