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2004 GTP misfiring & shifting hard from 1st to 2nd

J

justagirl

New member
I bought the car a month ago from a private owner, it seemed to run fine when I test drove it. With in the first day the check engine light came on and it was idling rough. Had the plugs, wires (used a/c delco) and fuel filter changed. Changed the front and back o2 sensor. Also, cleaned the throttle body. It still ran rough took it to the dealership, it was a bad catalytic converter, had a new one put on also had fuel system cleaned. It is still running rough! The other concern is it randomly shifts hard from 1st to 2nd, usually when its cold but occasionally even after it is warmed up.
 
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I would take it back to the dealer and tell them they diagnosed the problem incorrectly because it's still running rough. As for the trans, it's probably a bad pressure control solenoid. When they go the PCM commands maximum line pressure so shifts will be hard.
 
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