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P0121 code trans not shifting right

G

GTPWINDYCITYBOI85

New member
this car is driving me crazy ok i been having the p1200 fuel injector circuit code and my cylinder 2 misfiring but now im getting the p0121 but the problems is now when my service engine light flashing my car shift perfect but for the last couple of the days the light been solid and my trans act as if it dont want to change out of 1st gear and my boost guage getting stuck on 4 bars but if you drive around like for 10 minutes the light start back flashing and the trans start back shifting perfect i bought another throttle position sensor that didnt fix the problem i hope someone can help me
 


Check the wiring going to the TPS and the connector. I'm not sure why the misfiring would temporarily "solve" the TPS issue. I got that correct, right? That's weird.
 
Well as you probably know, when it's flashing, it means misfires are happening at that moment. I'm not sure if for some reason there's an override for the tps or what. Since the TPS light comes back right after a new one, I'd look into to that issue just by checking wiring and connections.
 
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Flashing is the pcm saying there is a potential catalyst damaging condition. While it's usually misfires, it can also be fueling etc.

TPS effects shifting as the pcm uses it for many things.
 
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