2002 Chevrolet Malibu

I drive a 2002 Malibu with the 3.1L V-6, auto,
cruise-control. Vehicle revs/surges/chuggles
200-500 rpm at highway speeds. Not all of
the time. It does it seldom under 60-degrees
ambient temp. We have replaced the fuel-
injectors, MAF sensor, and a brake-switch.
No go. We re-flashed the ECM. No go. We
replaced the torque-converter, torque-con.
clutch, pressure-control solenoid, hydraulic-
valve, shaft and sleeve. No go. Next, we
replaced the throttle-position sensor and
the ECM. No go. One tech sez maybe change
the valve-body in the trannie or replace it
all together. Another sez it could be a glitch
in the PROM. HELP!
August 29, 2006.

Check the EGR valve sometimes they will open when not supose to causing an internal vacuume leak. They can stick open due to a piece of carbon have it checked and cleaned professionally or replace it if found bad.

Aug 29, 2006.