2003 Impala police package with 90,500 miles is hitting the rev limiter in 1st gear around 43-45mph when accelerating at WOT (wide open throttle). Once the rev limiter is reached the engine begins bucking/sputtering/chugging and transmission will not shift into 2nd.
If the driver lets off the accelerator for just a second when the rev limiter is reached then gets immediately back onto the gas, the engine revs as if in Neutral. However, getting off the gas and waiting between 2 or 3 seconds when the rev limiter is hit before getting back on the gas causes everything to work fine - the shift into second will then occur.
When accelerating from a stop in 1st gear at ANY throttle position other than WOT the issue does NOT exist: the 1-2 shift occurs correctly.
No error codes occur when this happens, and no history codes exist related to this issue. The catalytic converter is not stopped up (exhaust was lowered and inspected with a camera). No other driveability issues exist.
A Genisys 2.0 scan tool was used during road testing and the "A" shift solenoid DOES turn off correctly (PCM turns solenoid A off to shift into 2nd), but the transmission does not shift into 2nd.
Transmission fluid and filter were changed, with the fluid found to be within normal limits (not excessively dirty or burned), and no metal flakes were found in the pan. After this service another road test was performed and the problem remained (fluid/filter change did not eliminate the problem).
A known good TPS (throttle position sensor) was swapped from another police Impala with no change - the problem still occurs at WOT, but the transmission will correctly shift into 2nd gear from a stop at ANY speed other than WOT.
Any ideas? Thanks very much.
If the driver lets off the accelerator for just a second when the rev limiter is reached then gets immediately back onto the gas, the engine revs as if in Neutral. However, getting off the gas and waiting between 2 or 3 seconds when the rev limiter is hit before getting back on the gas causes everything to work fine - the shift into second will then occur.
When accelerating from a stop in 1st gear at ANY throttle position other than WOT the issue does NOT exist: the 1-2 shift occurs correctly.
No error codes occur when this happens, and no history codes exist related to this issue. The catalytic converter is not stopped up (exhaust was lowered and inspected with a camera). No other driveability issues exist.
A Genisys 2.0 scan tool was used during road testing and the "A" shift solenoid DOES turn off correctly (PCM turns solenoid A off to shift into 2nd), but the transmission does not shift into 2nd.
Transmission fluid and filter were changed, with the fluid found to be within normal limits (not excessively dirty or burned), and no metal flakes were found in the pan. After this service another road test was performed and the problem remained (fluid/filter change did not eliminate the problem).
A known good TPS (throttle position sensor) was swapped from another police Impala with no change - the problem still occurs at WOT, but the transmission will correctly shift into 2nd gear from a stop at ANY speed other than WOT.
Any ideas? Thanks very much.