P0121 code after upgrades need help!
Thread Starter
Teching In
Joined: Nov 2018
Posts: 4
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P0121 code after upgrades need help! I have 1998 Camaro ls1. I had lots of.work done to it this winter. Went with 243 stock heads, 6,21lift came, 60lb injectors, fast 102 intake with fuel rails, a Holley sniper 102 throttle body. Ever sense the build I keep getting a p0121 code throttle position senor. I've changed the throttle body out twice along with the tps sensor and the other sensor above it. When the check engine light comes on the car acts all messed up. Surging when driving on the highway as if your pumping the gas pedal, stalling and also getting stuck at 2000s rpms. I'm at a all loss on what this could be. I have the voltage checked on the tps it was at 0.55 at idle.
