2003 Chevy Impala

Remove the plug wires from the ignition coils and check the coil towers for corrosion. Check spark plugs for carbon tracking(black lines down sides of plugs) or excessive wear.

Hi Again

Those all looked good. Can it be the modular valve on the transmission?

There is no modulator valve on the newer transmissions. It is possible it's a pc solenoid or tcc solenoid. You will need to observe scan tool data while the fault is occuring to narrow down the fault.

We have been having trouble with my 2003 Chevy Impala and threw parts at it left and right… mass airflow, pcv, throttle position sensor, fuel filter and many more… never a service engine light on. I thought it was my transmission, I really can’t afford this right now. I took it to a recommended garage and guess what guys??? After months of going back and forth 6to the parts store I finally found out what was wrong…I took it to a local garage and he asked me what was going on with it I told him and 30minutes later he told me what was wrong. It only cost me $140.00 to fix it… Check your car before going any further! It was my Catalytic Converter causing my car to almost stop when excellerating or climbing any kind or incline. After all that unnecessary work it’s fixed.