Have you disconnected the air tube, removed the throttle body & cleaned around the throttle plate diameter as has been suggested????

Use throttle body spray cleaner, but don't scrub, such that you damage the inside non stick coating on the TB walls.

While the TB is off, also check the throttle cable & accelerator pedal connections for binding or restrictions.

Have you again pulled the battery cables to reset the computer, so it can relearn it's cold & warm idle????

 

Well, Paw Paw... I've gotta be honest.... No, I did not remove the throttle body and clean it. In fact, I forgot that Mike had written that in there until you said something about it. I was so concerned about changing the IAC that I forgot. But, yes I did reset the comp by unhooking the battery. I have to leave my house in about 30 minutes to head off to work, so I will defintiely do that tomorrow morning and repost with the results. Now I feel like an ***...... Thanks!!

 

I forgot to mention that the accelerator cable and the throttle cable slide freely. That was the first thing I checked when the truck started doing it. I even put some lubricant on the cable assemble under the hood just to make sure it wasn't sticking.

 

I got the throttle body cleaner this past Sunday and cleaned the throttle body. Wasn't as bad as I was expecting. It was actually pretty darn clean, but then again I did put in a fuel system cleaner not too long ago. It still has not helped any. I also noticed something else on Monday morning as I was leaving for work. When my truck is running, I push the clutch pedal in to put the truck in reverse. With no a/c or defroster on, when I push the pedal in, the rpm's go up. When I release the pedal, they drop. I did this several times with the parking brake on to see if it was a fluke. It does it every time. I mentioned all of this to a friend of mine and he first suggested the IAC as well. His second guess is a vacuum leak, even though my CEL is not on. Any suggestions??

 

That's exactly what my truck was doing. Clutch in rpm's go up, clutch out rpm's went down. With that being said, I did not do what you did and try it with the parking brake on. I only assumed my rpm's went down because the truck was in gear, and letting the clutch out caused everything engaging causing the drop in rpm's. I would still suspect the IAC. My truck also had a "supercharger" type of wine when pushing in the clutch. After changing the IAC, that went away also.

 

Well, I changed the IAC and didn't notice any real improvement in the truck. I was kinda skimming through my Hayne's Manual the other day and stumbled upon the IAC section. It says that while the truck is running, if you disconnect the electrical connector from the IAC, the rpm's should drop. I did this just to see. My rpm's did drop, but not much. In fact, it was hardly even noticeable. I would have to say that a drop of 100rpm's would be an overstatement. Has anyone else tried this before? Should there be a major drop?? Or can someone try this and let me know?

I also tried to listen to see if I could hear a vacuum leak, but with the motor running, and not being real mechanically inclined, I could not hear one. So if anyone has any other suggestions, please, by all means, let me know. I'm getting pretty frustrated, but don't feel like paying a mechanic $80/hr to look at it.

 

OK, so we know the TB is clean & it & the contol cable aren't sticking, the IAC was changed & it helped but didn't cure the problem & a IAC disconnect test didn't cause as much rpm drop as expected, SO the vacuum leak idea has merit imo.

Question is, where to look for a leak thats so small it can't be heard????

Sticking open PCV valve, dryrotted rubber vacuum, or vapor recovery vacuum line, cracked vacuum diaphragm on anything from the brake booster, to EGR vacuum control system components, to the heater/ac system controls, to the vacuum actuated 4X4 system if you have that, a intake manafold gasket leak, & of course maybe Murphy's Law is mesing with you & the new IAC is faulty & probably some more things I've forgotten, belong on your suspect list.

 

First off, the truck is only 2wd. I prefer 4wd, but got a really good deal on the truck, or so I thought. lol

Secondly, that's alot of vacuum lines you've mentioned. Any place I should start at? Besides the begining? I will say this, that when I put the defroster or the a/c on, the rev's shoot sky high for a quick minute. I don't ever use the a/c and hardly use the defroster here in FL.

 

Hey, Unhook your battery first, then pull that throttle body off and clean it out. It gets stopped up by carbon it there just like that Idle Air Control Valve does. Don't clean it out while mounted because most cleaners aren't sensor safe. When you're done, hook your battery back up and test drive it. Also pull off that E.G.R. valve and make sure the carbon hasn't gotten to it also.

 

Ok, the throttle body has already been taken off and cleaned this past weekend. The EGR valve, I can take it off and clean it, but won't I then need to replace the gasket??

Paw Paw, as suggested, I've gone out to the truck and played around a little bit. I fired it up and unhooked the IAC E.C. and the rpm's dropped (Murphy's Law, the darn thing almost stalled). I'd love to check the PCV, but where the heck is it on the 2.5L 4cyl? Hayne's Manual says it's in the oil seperator on the left side. WTF is an oil seperator? As I said, I'm not mechanically inclined.

 

OK, good feedback, so on the second time around with the IAC disconnect test you got a positive result, with a noticeable rpm drop & thats what you should see.

Not sure why it didn't react that way during the first test you did, so for now set this aside, but don't forget it.

With the rpm going way up when you activate the A/C is a good clue, but I'm not sure just yet where this piece fits in your trouble shoot puzzle.

Does it idle WAY up like this Everytime you activate the A/C system?????

The IAC is supposed to idle the engine up a little, when a load is applied, so it won't stall, or run rough, like turning the A/C on, or when you turn the steering wheel & the P/S pump loads the engine, or when you turn on a heavy electrical load & the alternator applies more load to the engine, but it shouldn't shoot "sky high" even for a moment, to adjust for engine load. So this is a good clue.

Maybe suspect a vacuum leak in the control panel head, or the vacuum line to it.

The 4 banger PCV valve location is illustated on page 1-25 in your Haynes repair manual.
If it's due, or past time for replacement, I'd install a new one.
The rubber parts of this system are known for cracking & causing vacuum leaks, so inspect them closely.

 

So you don't wanna take off the EGR because of a $2 gasket that might be the problem anyway. O.K. Nevermind, I just thought that since I am a mechanic and you are "not mechanically inclined"(your words) that I would try to help out a fellow Ford fanatic. Good luck

 

Something else to consider: https://www.ford-trucks.com/forums/s...16&postcount=4

 

Rockledge, sounds like those posts might be right up my alley. I sat here reading forwards and backwards all the different links in them. The only question is... Where would I get that kit? That question was asked by another user and one person said to check the dealer. Any ideas?

Yamaha.... no need to be rude about this. I was meerly asking if I needed to replace the gasket. If you read my reply back to you, you can see it was just a question and I never said I didn't want to do it. Any and all input from any user is greatly appreciated. That's what keeps sites like this going is user input.

Paw Paw, I'll have to check on the a/c again for you. I almost never use the a/c just for the simple fact that the truck has windows. Guess it's in my genes. My parents never used a/c while I was growing up either. I'll get back later today with results.

 

Alright, so I had some errands to run this morning and after reading the posts you sent me to, Rockledge, I disconnected the electrical connector to the TPS. I left it unplugged about 5min, give or take. I noticed that the prongs on the plug look good and they are not dirty or damaged. I hooked it back up and left. The truck ran fine for about 30 minutes of stop and go with no problems. Idle was normal for that short period of time and then it started doing it again. So, question is, do I need to replace the sensor? Or get the "High Idle Service Kit"? Or both? Does that kit work? Nobody ever posted back to say wether or not they tried it and it worked or not.