Originally Posted by A.ross
p 507 was our code before new sensors were in. could throttle position sensor be a coulperate? Despirate to get on the road. Thanks.
P0507 is a high RPM idle code, which should theoretically be controlled by the PCM in conjunction with the idle air control valve on the throttle body. A faulty throttle position sensor could contribute to poor idle, but if the TPS was seriously out of whack, the PCM would throw a code for that too, I'd think, and would start ignoring the TPS signals until the code was reset.
If you have a multimeter handy, here'* a resistance testing procedure for the IAC valve:
1. Unplug the IAC valve connector.
2. IAC terminals A to B: 40-80 ohms
3. IAC terminals C to D: 40-80 ohms
4. IAC terminals A to C, A to D, B to C, B to D: open circuit (infinite resistance)
Terminal wire colors are as follows, according to Chilton:
A: LT GRN/WHT
B: LT GRN/BLK
C: LT BLU/WHT
D: LT BLU/BLK
You might be able to check whether the TPS is having an effect on starting just by pulling its connector; if the PCM detects an open circuit to the TPS, it'* supposed to default to some safe value.
Don't know if any of this helps, but...