Getting a PO121 code

1998 PONTIAC GRAND PRIX
124,000 MILES • 3.8L • 6 CYL • TURBO • FWD • AUTOMATIC
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P2HENNESSEY
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Replaced pedal/throttle position sensor but the code came back two months later. The car starts running rough when the code is thrown. What else do I need to check or do since the code is back?
Oct 13, 2017 at 2:38 PM
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MHPAUTOS
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check for a problem with the loom, check for any loose or corroded terminal pins, do a wiggle test, that is with the engine running. wiggle the loom and see if you get any reaction. you can get wire fractures from vibration and this is on way of locating these problems.
Oct 13, 2017 at 4:30 PM