Toyota Repair: Throttle Position Sensor, throttle position sensor, bad throttle position sensor

Question
Hi Ted,

I have a 1995 Camry 4 cyl engine. This is not a Calif engine as I am from Pennsylvania. I am wondering if my Throttle Position Sensor may be going wacky.

I had idling issues last year. I cleaned the idle control valve removing it from the throttle body last year. The car idled better.

There was another problem causing an intermittent miss in the engine. I found oil leaking into the distributor from the shaft for about a year before I discovered it. This caused the coil to not fire or misfire at times. I replaced the rubber O ring and the miss went away for three months.

I now have an intermittent miss again. It happens while driving after the car reaches the normal operating temperature. The miss will not start until I have driven at least 4 or 5 miles past the car being at the operating temp. The car does not always miss though. Once it starts missing, it keeps missing until the car is turned off.

There is no check engine light on. What are the chances that this missing is a symptom that can be attributed to a failing Throttle Position Sensor?

My car has issues idling. The idle jumps from between the range of 750 to 250 and then to zero. This erratic idle does not happen every day and only happens when slowing down for a stop sign or a turn and the tack is under 1K.  

When I try to start my car after it stalls, the engine will not start unless I depress the gas pedal. Otherwise I can crank and crank the engine and nothing happens. What are the chances a bad Throttle Position Sensor will cause this idle jumping up and down?

If I need to replace the Throttle Position Sensor, what is the difference between buying an aftermarket product with a 2 year warranty and a genuine Toyota?

Many Thanks Ted!

Sincerely... Mike

Answer
The TPS is not the problem, it won't cause a misfire, intermittent or otherwise, sometimes cleaning the IAC valve doesn't work and it needs to be replaced. This may be the reason for the low idle, there may also be another problem because the IAC valve does not cause a misfire. Recheck the distributor again to see if oil is in there again and if so replace the distributor. If there is no oil remove the rotor and the coil cover and check the coil for cracks or burned areas and replace the coil if necessary.