HELP!!!!

I have been having an idle issue off and on now for a few months now and i feel like im chasing a ghost. its a low frequency problem like once a week. i will be in neutral and the rpms will rise on their own non stop until i shut the car off or put it in gear and drive. sometimes when i get on it and accelerate fast and go to shift gears but stay in neutral it'll drop rpm very fast to just about 500 and want to stall. sometimes it does stall and sometimes it corrects it self. nearly 90 percent of the time my idle hangs in between gears and very slowly goes down if i rev up the engine. i have only thrown one code. a P0133 which is oxygen sensor slow responce.
i have completly changed the throttle body out to a brand new one. ford racing 62 mm. I cleaned the MAF sensor. cleaned the cold air intake. replaced the O2 sensor. changed the fuel filter. i took it to two diff shops for diags and the car wont act up while its there so they cant tell me anything.
i have a cold air intake. ford racing 62 mm tb. programer. long tube headers off road h and flowmaster mufflers.
if anyone has a clue please help. thanks

 

Try posting this question in the appropriate Tech Section. This is the Forum Feedback.

Good luck

 

Moving to tech. ...

 

try reverting back to the stock tune for a while and see if the concern goes away, it could be a problem with the tune

 

I'd check out the injectors as well as run a tank or 2 of SeaFoam.

 

Since it has to do with idle, I would look at the idle air control valve. You say the throttle body was replaced, but was it a shell that you put in the old guts? Or an entirely new assembly?

Another item to consider would be the gas pedal assembly. If you have a tuner, you should be able to see throttle position in datastream. See if it is doing exactly what your foot is doing. A bad pedal assembly would not make it come close to stalling though. Only the IAC valve between those two items.

 

S197's do not have IAC valves

 

true story^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

OK. So no IAC valve. Which still comes back to what controls the idle speed. So, was the guts of the stock throttle body put into the new one? Or was the entire assembly replaced, motor and all? Motor meaning, the motor that opens and closes the butterfly. When I had to deal with this at my shop, the entire throttle body had to be replaced to get the IAC valve, or so the Ford parts guy worded it that way.

 

Sorry for such a late response...
My understanding is if I put the car back to stock tune it wont run right given the mods I have. As far as sea foam I tried putting some in the vacuum line but every time I pull a line off it stalls the car immediately. I did pour some sea foam in the gas tank. I replaced the entire tb ro a ford racing 62mm.