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P0121 Diagnostic Trouble Code Discussion for December 2004

Throttle Position Sensor Does Not Agree With MAP

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Trouble Ticket Help Requests for DTC P0121
Help Request Posted
1995 Mercury Grand Marquis LS 4.6L Poor Idle Quality VIN: 2MELM75W8S
P0121: TP circut problem. I have this Merc. that likes to surge the idle speed up and down about 100-150 RPM's at stop sign's sometimes.Makes no difference if engine cold or hot.Sometimes it will idle just fine.Looked into throttle plate not much sludge buildup. I did replace IAC motor...
December 07, 2004
1998 Chevrolet Express 1500 5.7L MIL Lamp on VIN: 1GBFG15R6W
P0121: TP Sensor Performance. This is an emissions failure... Replaced PCM and tested all ground circuits to PCM Replaced TPS and re-wired circuit from TPS to PCM Replaced MAP Sensor/MAF Sensor/Fuel tank pressure sensor/both rear O2 sensors/both catalytic converters. While running drive tr...
December 09, 2004