moosestang

Well in that case the throttle body is the IAC valve and you've all ready replaced that once.

What's the fuel pressure look like when this happens? You really need a scan tool to diagnose this problem or you're wasting your time.

Did you try flashing back to the stock tune, sorry if I missed it.

simplexdesign

Fuel pressure is fine and I do have a scan tool. Right now my stock tune isnt working because of the dealership reflashing my computer. Hopefully brenspeed can get that sorted out so I can try putting the stock air box back on even though I dont see how that could be the problem since the CAI was on for 2 years before this started happening

moosestang

Well I'm stumped. I assume you cleaned the throttle body inside and out with TB cleaner or brake cleaner when it was removed.

simplexdesign

Yup TB was cleaned and then replaced then cleaned again.



I am really surprised that no one else on here with a manual has ever put their car in neutral at 40+ mph and let it coast to see the rpms jump up and down

shanec

I see it occasionally, mainly when the outside temp is cold. I just got in the habit of letting the thing gear down (coasting in-gear), then pushing the clutch in before the engine starts lugging.

gatkins94

OK...Mines doing the same thing, so I read this entire thread hoping to see the answer. So I guess I'm just bumping this to the top in hopes someone else has tried. Mines getting so bad that if I don't find the answer soon, I'll have a new car.

I have an 07, manual, GT. I replaced the "H" pipe with an "X" pipe, have Corsa axle back exhaust. Breenspeed 93 tune and some kind of aftermarket intake (I can't remember what it is while I'm typing this. lol) I recently replaced the fuel filter, cleaned the air filter, replaced the plugs (2 broke! the TOOL to get those out is amazing!) and it's not helped at all. This weekend will be the throttle body cleaning, and the MAF sensor cleaning, but I'm thinking this isn't going to help based on the previous posts.

oh....and it's got 102,000 miles on it!

simplexdesign

I still haven't figured mine out but I am taking it back to Ford this week and I will post whatever I find out. I doubt it is mileage related since mine only has 25k on it

gatkins94

Certainly keep me posted on whatever they think it is. It's running like the IAC valve would be bad, but we don't have an IAC valve....so it almost has to be whatever replaced that, and that would be the throttle body. You've already replaced that....so it seems that can't be the issue????

I think mine got worse after I cleaned the MAF and the Throttle body, it's doing it all the time now, it use to only do it when I first started the car in the afternoon leaving work, but now it's almost every time it drops back to idle, it'll jump from 3-4 hundred all the way to a thousand constantly...it's very annoying.

SUP3R D4VE

I actually started a thread like this a few months back. I have the same problem and no one has had a correct answer! Ive cleaned and cleaned and cleaned and nothing! I have noticed that it is more frequent and more severe when i have less than a half a tank of gas. If i keep my fuel tank full its not as bad or often. Have you all noticed if thats happening to you? I thought it might be my fuel pump but being that it still happens with a full tank of gas it couldnt be that could it? Im stumped and out of answers!

gatkins94

It doesn't have a pattern with regards to fuel level, and I drive mine a LOT, with all different levels. I have 103000 miles on my 07, and drive about 110 miles per day, so I would be able to tell. I've purchased a new throttle body off of ebay that came off a car with 10 miles on it (At least that's what the description says) and it has the idle position sensor on it, so if that doesn't work, I'll be at a loss too. I'll keep you posted.