SN95 5.0l TPS Voltage WAY TOO HIGH!!! Please help!

[JulianSerna]

Originally Posted by BowTie Eater 5 Liter

well, i thought my throttle positioning sensor was my problem, so i purchased a brand new one.

what was happening, was the tps was showing 4.79 volts.

i tested all 3 wires
grey wire 4.79ish volts
grey/white wire 4.79 volts also
brown wire 5 volts.

what could the problem be? i replaced the sensor and ive still got the same readings. i can not think of anything else that could be the problem. if someone else could make a suggestion, that would be greatly appreciated.

Thanks, Kris

I played with this problem and did the TPS test, everything. The problem is that the SN95 ECM has a pre-programed parameter called Hi Speed Idle Offset and Another called Active Above VSS. You need to have a tuner change this parameter and set the Hi Speed Idle Offset to 0, rather than the factory 200+ RPM. If you want to confirm that this is the problem, temporarily disconnect the VSS sensor at the transmission, drive around with your Speedometer not working, but notice that this has solved the high idle problem as the ECM thinks the car is at 0 MPH. If this gets rid of your hi idle problem, then you know for sure you need to have a tuner disable the above mentioned options.

I did this on my car and the tuner just changed the parameter on a Diablo Chip and the problem was solved.

Good luck with this ....