How to fix engine surging Impala
Chevrolet Impala 1999-01 may experience Engine surging at highway speed. While this may be an air fuel related problem, it can also be caused by a slipping torque converter clutch. This happens when the torque converter clutch (TCC) is not fully applied. GM refers to this as a slip/stick condition.
The TCC is applied with fluid pressure from a solenoid valve in the transmission valve body. The solenoid is pulsed by the PCM. In this particular model, Chevrolet has experienced some electronics failures where the pulsing is not correct. The result is a slipping TCC that can burn the transmission fluid and destroy the torque converter.
If you experience a surge at highway speeds above 40MPH, first check the transmission fluid to make sure the level is ok. Then check the fluid color. If it is dark brown and smells burned, you may have to pull the transmission and have it rebuild. But that’s not the full repair. You must also replace the PCM with an updated unit to prevent this from happening again. Chevrolet fixed the problem in the 2002 model year.
© 2012 Rick Muscoplat