Two questions I have on my 93 truck. Question One, What sensor could be causing my truck to idle poorly shortly after start-up? I start the truck up and it runs good at first, then I drive a few miles and whenever I stop at a light or sign it tends to act like it wants to stall yet is doesn't stall. Once I've been driving a little while it idles fine at stops. Second Question, What could keep causing my light switch connection to keep melting enough that I have to replace the switch once a year or so? I can smell a melting smell every once in a while and then eventually I have to replace the light switch connection in my dash because it has melted enough to cause lights to not work properly? Any advice is helpful. I have a 96 F-150, 93 F-150, 86 F-250 6.9L and an 84 F-150.

 

I had the same issue in one of my other trucks a little while back... After the 3rd switch I talked to the dealer and they recommended changing the plug that connects to the light switch... I was skeptical, but did it anyway with a new switch, and haven't put another in it since.... Try getting a new plug along with the switch if yours is bad if not change the plug... Good luck... Not sure on your other issue

 

Your poor idle could be caused by either the throttle position sensor or the idle air control valve.

 

You need to pull codes.

 

Thanks for the reply guys. I will look at the IAC and Throttle positioning sensor. I tried pulling codes but it doesn't seem to be throwing any codes. It's weird. After I've been driving for a little while like after it's all warmed up it idles fine.

 

Same thing my IAC did until I cleaned it.

 

What method did you use to clean it?

 

If I remember correctly, I removed it and and cleaned it with carb./fuel injector cleaner, being careful to keep the cleaner out of the electrical connection end..

 

Clean it with sea foam and clean the throttle body while your in there. I use an old tooth brush to scrub all of the carbon off and suck a bottle of sea foam into the engine thru a vacuum hose stalling it out at the end. Let it sit about 1/2 hr then run it hard until the smoke stops. You may be impressed with how it runs after.