sticking idle 2001 sport 4.0

[faron021]

hey guys, i have read and read until im seeing double and nothing has helped me.

the problem im having is setting in park idling about 800-1000 give it any amount of gas (reving) when it idling back down it sticks about 1500 for about 1-3 seconds then back to 800-1000. it also does it when driving.

everything i have checked/fixed so far that may be relative. swapped/cleaned maf (no change) swapped/cleaned IAC (no change) cleaned/adjusted TB (nothing) check for vaccum leaks (none that can be found) TPS (fine)

this is one other things to throw in this odd mix. when i unplug the IAC not one rpm change, that would mean a vac leak but i cant find any. however i unplug the air line going to the IAC when its plugged in it is sucking air, i block off the air same thing no rpm change, i unplug the IAC and i lose the vac on the line, meaning the IAC is ok and not leaking.

I have got a P1506 cel twice but its went away now.

the tb is closed all the way. i know for sure the TB cable is not sticking, as this does this with the cable unhooked and just reving it right form the TB.

my other thing is if i have a vac leak im getting enough air to feed the motor but yet i do NOT have to lean codes bank 1 bank 2. my mom had one a long time ago and she had those codes (fixed with change the intake gasket) however i already did this on mine.

dont know where to head to. i work at ford on top of everything else, and no one there really knows what to do next or just want tell me. one of the techs there said to try and reset the computer. that didnt work thru.

any thoughts would be a help. thanks

 

[swshawaii]

PCV valve changed? Not the common symptoms, but check the PCV elbow as it doesn't always throw codes. GL

http://www.explorerforum.com/forums/showthread.php?t=314670

 

[faron021]

well to test if anything in the pcv lines was leaking i just bypassed everything to test. and yet again no change. only thing im wondering is if the intake gaskets have gone out i used fel-pro name brand. but i sprayed all around everything and nothing changes.

the only other possible thing i could think of would be the can-vap, but usually they throw a cel when they go bad. unless theres some vac leak between there and the intake.

other then that sticking issue the thing runs great.

any other thoughts.

 

[boominXplorer]

I bet its a weak IAC valve. I cleaned one one time and it had a sticky high idle after. I took spray silicone with a straw and lubed up the slide and seat inside. Was back smooth after.

 

[faron021]

well so far im out of no money but theres really nothing left to do or try. I know its not the IAC i have tired/switched/unplugged/swapped/blocked off. and everything else you can think of and nothing has changed.

forgot to mention one thing earlier when you crank it up doesnt matter engine temp ect. not sure excatly have to explain it, other then, like having your throttle half way if not all the way open while it started up, a big rush, as soon as it fires, for like 1-2 seconds. it really sounds like its getting to much air.

it might just be a tired and old engine, might be coming to end of its life, 130,000 id say its had a good run so far, i brought it with about 90,000 not knowing how it was taken care of in the past.

its just bothering me that the only way i can get it to stop the sticking is to unplug the IAC, but when i do, it idles a little rough, and the air line going to the IAC has no vac. plug the IAC back in the idle smooths, the vac is back, and so is the sticking.

this weekend im going to pull the whole intake off and use ford gaskets upper and lower, and also see if anything is off. had to order the gaskets waited to late today to tell them i needed some it will be wed before i get them.

i can simplify this for everyone. everything is running fine, just as soon as you give it a little gas, im talking a 200rpm up it will stick there for about 4-5 seconds and go back to 800ish. i dont have a rough idle, i dont have a high idle. its like the TB is sticking open for 4 seconds then closing, but so far there are no vac leaks, or any sensor valve that is not working correctly.

i'll see what happens saturday.

 

[faron021]

well think im giving up nothing i have done has done anything to improve this. new parts sensors, hoses, test after test everything shows up good. unless the actually ecu is bad, but thats a little odd if thats all thats wrong never seen one only do that. but who knows. might be trading it in in a little while.

its driving me nuts that i cant even pin point it down much less fix it. every ideal i come up with or hear about gets shot down as soon as i try it.

only thing left to try is a new tps but every test ive done shows it to be working just fine.

i dont know anymore and just about to the point of burning it down.

 

[faron021]

update: i got a new tps nothing changed. i got a little mad so i started taking things off started with the tb when i put it back on a screw fell somewhere, couldnt find it. i got even madder so i put my anger to good use and pulled the whole air intake off down the the block, supprised it was actually pretty clean. anyway it was to look for the screw but while it was off i looked at all the gaskets everything was good but i firgured while it was this far down i'll make sure it cant leak for a long time. so i took red rtv and put where every gasket was also, pretty much to sum it up, everything that had a gasket in the intake i added rtv either red or blue if a sensor was close.

a funny thing happened it didnt change a thing. however when she got in it to leave i have had it by this point. it sounded different when she left, she went to get gas and when she cranked it up there it almost didnt want to keep running and then said it sounded like a puppy dog wimpering then said it was fine on the way home best its ever ran.

odd since i reset the ecu i dont know how many times, but whatever its fixed for now till that cheaper non ford iac goes out but ill wait till then to fix it. so i guess there was a vac leak somewhere but never threw a lean code. like i said its fixed oh well.

done.