Ok, I have a 99 F150, 4X4, 4.6L, Ext Cab. I have been having problems with my truck Idling very high between 2500 and 3500 RPM's. I took the IAC off, cleaned it, it ran fine for about a week. Then it all started over, I then went and bought a new IAC, put it on went about a week, and now it has started again. Both times I disconnected the battery to reset the computer. What else can I check.
Since the attempted IAC fixes failed after a certain amount of time , something must be infecting/compromizing the valve.
Verify the condition is not caused by throttle body sludging, throttle cable binding, or interference between an improperly positioned floor mat and accelerator pedal, just in case..
Inspect the inside of the clean air tube at the PCV closure hose connection for presence of moisture, oil, or oily stains. If evidence of PCV system backflow is found, replace the PCV system with the revised PCV Service Kit, YL3Z-6A603-AA.
This hose is a direct line from PCV valve to the IAC. It plugs into the rear of the manifold behind your IAC (If you have a TB rear mount IAC) - This would be the the line to reference -
Replace the PCV Valve and clean one of your IAC's up to test. Also, it's possible the line pictured is collapsing do to deterioration . These lines fail often..
Ok, I checked the pedal, and floor mat, I cannot find the PCV Valve, I need to let the truck cool off, and the temp outside cool off (102') I will check it tonite, which tube are you referring to in the picture? Is it the long one pointing to the right, or the big one on the bottom with 2 lines coming off it? Also I didn't mention in my first post, this problem is intermittent. Usually when I have driven for a bit, and I can tell when its happening while driving by the fact that when I let off the pedal, the truck doesn't slow down much, and if I am going downhill, it actually speeds up a little. When I stop is when I can tell the rpm's, and I have never had it start while just sitting idling. Also I can rev the engine 1 2 or 3 times, and that usually resets it.
Last edited by Flametamer123; 08-16-2007 at 04:11 PM.
maybe i'm just retarded, but i'm having some problems with this. the PCV valve that the dealership gave me has a 90 degree bend in it, and i checked the hose coming off the valve cover behind the oil filler neck and i can't see how this valve i have can fit into there. i know that hoses cover the ends of the valve, but i can't seem to see the actual valve in any of the hose system.
so i checked my owner's manual today, and it says that i need a PCV valve part number EV-243 for the 4.6L. the one they sold me at the dealership is part number EV-233, which is for the 5.4L according to my manual. i called the dealership and they said it depends if i have the windsor block or the romeo block, whatever the hell that means (and how do you even tell?) but basically i get the impression that the dealer has no idea which one i need for my truck. i'm pretty sure i have the wrong one right now though because i can't find anywhere in the PCV system that this valve with a 90 degree bend in it will fit. maybe the proper one is straight and not bent?
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