IDLE

[PEPPER]

I HAVE A 02 SILVERADO 4.8L AUTOMATIC. THE PROBLEM THAT I HAVE

IS WHEN THE TEMP OUTSIDE IS BELOW 50F. MY TRUCK STARTS FINE

AND THE IDLE WILL GO UP TO 1K AND THEN DROP DOWN TO 600 AND

THEN SURGE BACK UP AND DOWN. SORTA LIKE THE OLDLER AUOTMATIC

CHOKE. BUT AFTER A FEW MINUITES OF WARMING UP THE TRUCK RUNS FINE

WITH NO SURGING AT ALL. IF THE TEMP IS ABOVE THE 50F THE TRUCK STARTS

UP AND RUNS FINE. DOES ANYONE HAVE ANY IDEA OF WHAT I CAN CHECK TO

SEE WHY THE COLD START IDLE IS DOING THIS?

[black77gmc]

Try checking the IAC (Idle Air Controller) it only works when it is cold and when the a/c is running, it sorta acts as the choke for a fuel injected engine. check a maunual for testing procedures