Can a Throttle Switch Cause A up and down in the RPMs ? That is the problem that I have been having I have done every thing else. You have to remember the car has over 270,000 miles and I dont think this has ever been changed. Can you tell me also what does this item do?

 

It may possibly be. Let us suppose you experience the engine at cold start idle high until the temperature has reached the point where the ECU is triggered to lower fuel sent. This is normal, no? Normally I would see perhaps 1,500 RPM for 5 minutes then drop to below 1,000 when warm. However, suppose the idle is surging at 2,000 and even when warm is at a closed throttle (foot off accelerator) RPM of 1,500. This may indicate that the throttle switch, if equipped, is not being initialized. I have experienced this most likely to be from the throttle switch/throttle plate screw to be just barely out of adjustment. Be sure, take out your throttle body and find a quiet place to tinker, turn the throttle plate and listen for a click, a tiny precise click. Use reason to deduct the basic mechanics of the switch's activation and the swivel action of the throttle plate. You may summize that there is a tight tolerance and the screw which retains the spring action in relation to the throttle plate's clearance of the inner diameter of the air channel is the mechanical aspect to focus on. A simple turn to where there is sufficient force for the click but that you can still see light from the tangents when looking through with a light source above you head.

 

How do you adjust the sensor does it need to be adjusted. I found that it was the sensor should I replace it or can it be adjusted that car is a 1993 240

 

Check the throttle linkage bar first. Make sure it's extended enough to where it will not interfere with clearance. If it falls short the switch will not be able to be initialized.