Hey guys just seeing if anybody else has experienced this.. I started up the truck today to head to work took off, went to shift into 2nd and noticed a jump in the engine rev's..Now this has happened before and it normally just worked it's way out but not today.. It did this all day.. When i first start it up it has a crisp clean idel but when i get into the petal and start going through the gears it's like something is keeping the motor at about 3500 RPM's.. It was so strong that it would pull the truck through the gears without me having to touch the petal.. Now i called up FORD and they say it sounds like a IAC valve.. So when i get home i searched here and most the people who have had to replace the valve didn't speak of the strange idle just a humming noise.. SO has anybody had to replace the $80 IAC valve because of this issue or can anybody think of what it might be if it's not this.. help is much appreciated before i throw $80 to the parts man..

Thanks, jeremy

Edit: forgot to add it's a 93 2wd 2.3 motor with manual tranny..

 

I replaced my just the other day on my 98 2.5L. I paid 50 dollars at Napa for the IAC. I would get one there.

 

Ok put a new IAC on today and it's doing the same thing.. Any ideas anybody??

 

It MIGHT be the Throttle Position Sensor causing the IAC to be open. Check the voltage on the gray/white wire with the key on and the throttle closed. A good sensor will read between 0.50v and 1.25v when the throttle is closed.

If the closed throttle voltage is over 1.25v, the sensor is telling the PCM that the throttle is open when it is not. Above a certain minimum vehicle speed and when the throttle is reported open, the PCM will put the IAC in dashpot preposition mode (partially open). This can cause the RPM to hang.

 

how is the throutle bdy its elf if its got carbon clean it and put a new tps( ranges are known for tps problems)

 

yep I've had to replace my TPS on my 98 2.5 twice within a year. It's an easy fix right beind the TB. Black plastic lookin thing with a 3 wire connector going to it. Hope the TPS helps it -Mike-

 

it may be a bad TPS.. I assumed that it was some other issue when the problem continiued when i put the new IAC on today.. So i took the IAC back and got my $93 back from advanced.. So i finally got fed up with it and took it up to a local place today and told the guy whats going on.. He pulled the harness off the IAC and the problem was instantly fixed.. At first i thought i had possibly got a faulty IAC from the parts store but if the TPS controls the IAC this is a good possiblity.. When i took the cold air intake off today i noticed a oil'ly residue in the bottom of the Throttle body..I would have cleaned it then but there was a sticker on it that said something like DO NOT CLEAN.. I think tommorow i'm going to take my IAC off and clean it really good along with the throttle body..From there i will test the TPS out and hopefully thats it.. I got the harness off now and it's running fine so i'll see how it goes.. Thanks alot for the ideas guys i'll let you all know how it goes..

Jeremy

 

check pcv valve.

 

I have a 98 2.5 w/ manual trans. And i have the exact same problem. i replace my idle control valve and its back to normal.