My 94 4runner makes this wierd humming noise when I come to a stop. At first I thought it was low power steering fluid but it wasn't. I beieve it might have something to do with my TPS (if the TPS is the black cap on the the throttle body). Everytime I tap the cap with a screwdriver it makes the noise disapear and makes the truck change idle. I hope this makes sense to someone out there. Any suggestions?!

 

Anyone????????

 

well, i think youve pretty much narrowed the problem down to the little black cap thingy-- if it is the TPS, keep in mind that most of the wear on one of those sensors occurs at the beginning ( near the low RPM side ) -- or it could be the IAC "idle air control" valve that controls the idle-- though i havent been under the hood of a gen 2 for about a year. Try changing the TPS-- it cant hurt if you have over 100,000 miles.

Tim