RPM fluctuates TPS ohms or volt readings
I have a 1999 Intrepid, 2.7 which is having problems with RPM fluctuations, and I believe it could be the TPS sensor. I tested the resistance of the power (VT/WT) and sensor ground (BK/LB), it reads 4.2 ohms (good so far). Then I tested the sensor signal (OR/DB) and sensor ground (BK/LB), it reads .5 ohms (good so far), then I gradually opened the throttle to WOT, it reads, 3.0 ohms (not good, I think). So I decided to check the volts. The volts of the power and sensor ground reads 4.9 volts (good so far), then checked the volts on the sensor signal with the ground on the car, it reads .6 volts (good so far), then while gradually opening the throttle to WOT position, it reads 3.7 volts (not good I think). In my Haynes Manual it states “gradually open the throttle – the voltage should increase smoothly to approx. 4.5 volts at wide open throttle. If test results are incorrect, replace TPS.”
Now here’s my dilemma: since the manual covers different models and engine sizes, I called the dealership to see if there was specifics regarding the volt ratings for my car (forgive me if this seems foolish, but this is my first experience in troubleshooting a vehicle, I am only beginning to learn through this forum, the FSM, and my Haynes Manual). Anyway, the mechanic says that 3.7 volts seems about right. So now I’m confused, is the book correct or is the mechanic? Could someone please tell me what the proper ohms or volt readings for the TPS are? Is the sensor bad? Does it need to be replaced? I have already put too much money into “false” repairs (replacing sensors, fuel injectors, etc.) diagnosed by mechanics. Your insight would greatly be appreciated.