I am trying to check a possisble reason my truck will not slow down on idol and when it does for a short time it comes right back to idol that is too fast causing banging shift.
Don't know a great deal about the double throat throttle body but watched a few videos that said they could cause this if the plate closed has gaps and light will go through , shinning a flash light from one end seeing light around the plate is a definite. its not a huge gap but it is easy to get light to shine through. Is it practical to assume this could be the cause the idol is stuck at 800 + and wont go down?? I have a new tps, a new iac and a new map sensor. I have checked for vac leaks and nothing.
If this is possible ?? next question, Is it practical to rebuild these throttle bodies there not available from ford any longer and all are remand parts. . Also any other ideas please let me know.
grumpy

 

Usually, the throttle bodies give very little trouble, so,,,,,,,,,,,,,

Has anyone been in there changing any adjustments?
Did this problem come on after some work was done?
As far as vacuum leaks, are we sure the intake manifold is not leaking at one of the intake ports ?
Many times unmeasured air (Vacuum leak) gets in and the o2 sensor sees a lean mixture and the PCM attempts to correct that resulting in more fuel and higher idle speed..

 

Thanks Hanky
No I bought the old truck very nice one one owner but 192k on the clock. The idol has been off since then, so I changed the tsp, the iac and the map sensors and the truck runs better smoother I think but idol is too fast. Maybe im not seeing something but this monster wont idol down, the plates are fully closed so adjustment should not be the problem. I cant say about the intake vac leaking but I shall certainly check it out.. The thing about the throttle body having light leaking around the closed plates made sense but seemed like it shouldn't be that touchy so I thought id check it out with you guys. Is it possible to hone the bores and replace the plates in these throttle bodys?? If I don't find anything else?
Thanks Grumpy

 

You shouldn't have to do any major work on the throttle body. All tests and checks MUST be done with a warmed up engine.

The plates should close but not so much as to cause the plates to stick in the bore.
Sometimes simple things like the linkage sticking or messed up get overlooked.
Something you might try if you haven't done it yet.
Remove the negative battery cable for several minutes, go have some coffee, then reconnect the cable start the engine , goose the throttle once and let the system adjust the idle speed which it should do automatically. This can take several minutes. If there are no vacuum leaks it should come down to approx 600 RPM in park/neutral.

 

Thanks again Hanky;
I have been checking out the throttle body and I think the springs and linkage are worn as well as the light gap, I see its pretty worn with nearly 200k on it. I picked up another salvage yard tb today and I will do some switching flipping flopping or whatever and see if I can pinpoint something that is the problem. Grimlins are usually very obvious you just cant see them.
Will let you know
Thanks
Grumpy