roegs

I've been chasing a stumble in my '09 GT (85k miles) that occurs sometimes when taking off in 1st gear from a light. Its just enough of a stumble that it feels as if the engine will die as I'm letting out the clutch. It usually catches itself then and takes off. It does not always do this. I've changed plugs, O2 sensors, TPS sensor on the TB, cleaned the TB a couple times, reset the computer, and added a tune. All have helped to some degree, but its still there. There are no error conditions logged.

I was recently reading an article about throttle bodies and the author said that Ford considers them to be a normal maintenance replacement item. I find this hard to believe, but then again searching through the forums (this one and others) it seems there are quite a few TB's replaced. I can pick up a new Ford Racing M-9926-MGT TB for around $175, and its a direct replacement - same bore etc. Are there wearable items in the TB that would warrant replacement?

Derf00

Reference article please? I've never heard of a TB being a normal maintenance replacement item.

Also, you could just be letting out the clutch too soon or too much too soon which is why you are bogging.

How about basic maintenance items replaced like Fuel filter, air filter, spark plugs?

There's also a gas pedal calibration that gets rid of some of the lag there can be.

http://www.modularfords.com/threads/...-Wire-Throttle

roegs

Here are a couple references to throttle body replacements:
http://www.f150forum.com/f4/should-t...-12619/index2/
http://www.dallasmustang.com/news/20...-2010-mustang/

It seems that some have wear on the throttle shafts causing a vacuum leak. All the filters etc. have been replaced. If I was letting the clutch out too soon it would do it all the time. This problem is intermittent. It seems to happen more if its been idling for a while (long vs. short light). I've also done the pedal calibration thing many times.

I find it interesting that FRRP even sells a direct replacement. Just for them to offer a direct replacement would indicate that quite a few are replaced.

tbear853

They can wear just as a carburetor does when it's shaft wears the bores into egg shapes and the butterfly doesn't center in the body as it once did, there is a fair amount of "weight" against the butterfly at idle, low speed, and especially at closed throttle high speeds.

But.... that's not to say they are expected to wear out in only 85K miles. I got a '92 Tbird Sport 5.0 with near 155K that still has a tight throttle body that idles and runs like new. I've seen many CVPIs go well over 150K miles with oem TB and no issues, and they go WOT a lot.

But stuff happens, every once in a while one does need replacement for some reason.

Nuke

I've owned quite a few fuel injected vehicles that I've put over 200k miles on with not a single TB issue. I've been on the boards for double digit years and it's rare to hear anyone say that they HAD to replace a TB. NOT THAT a I haven't seen it; just very rare.

If you DO replace your TB, I seriously recommend an identical OE replacement. There are too many folks that changed their TB's, looking for performance (won't happen unless you're heavily modded), and they have a lot of problems getting the car to run right.

roegs

Last week in a moment of weakness I clicked Buy Now for the FRPP M-9926-MGT throttle body. Before installing it, I looked it over pretty careful. From everything I could see, its identical to the stock on I had on the car. Casting numbers etc were all the same. The only difference I could see was the Ford part number sticker, and the FRPP unit was one rev higher.

Before I talk about the new TB, a couple items about my old one. First, its was squeaky clean - no deposits anywhere on the butterfly's or bore. Second, I had replaced the TPS sensor with a new Ford unit approx 2000 miles ago.

I installed the new TB, torquing the nuts and studs to specs. I also went through the pedal calibration process. After 3 days of driving I can say that there definitely is a difference. The lag and hesitation are gone. To me it feels much more like my old drive by cable (vs. wire) cars - the engine responds much more like I feel it should when I work the accelerator pedal. My opinion is that the new motor assembly is what made the difference. In my case, the car is manual transmission and in just under 90k miles the original TB motor has opened and closed the TB shaft many, many times. The gear mechanism felt smooth, but possibly the TB servo more gets less responsive as it wears?? I see that Dorman makes a replacement TB motor assemblies for our cars, and that might be a good solution also for those considering replacement of their TB.