Thomas08GT

First post and new account but have found this forum useful for awhile now. I recently upgraded from a 99 to an 08 GT in the past month the car has 65k milesI've installed air raid cai, genavillalalala 62MM Throttle body. Charge motion deletes, Ford racing hot rod cams, pypes cat back, 3:73 gears and of course have the bama tune. Doubt it would be a factor to the problem but also have the hurst shifter. The car has started jerking or bucking at low gear low rpms recently to the point that if you don't change gear it'll give you whip lash. This only happens when first driving it cold or warm. Yesterday the normal knock most of us here when changing gear cruising around town became a repetitive knock while out of gear sitting at a light. I pushed the clutch in and it magically stopped. I'm going to guess the two of these are connected i would assume clutch how ever my diagnostic skills are lacking. Any input would be appreciated. And yes I've tried searching with no answer close enough to start tearing the car apart. Thanks. Side note all of these have been installed within the past two weeks so I couldn't tell you if it started at anyone part

howarmat

Assuming the tune is correct it could be the clutch maybe. But that is a lot done at one time so and it could be an airflow issue.

Thomas08GT

I checked vacuum right behind the throttle body and its sitting at 17" it seems the average for horrod cams is 15" if that helps with anything fuel pressure is good as well

Thomas08GT

I'm stuck on thinking it's the clutch because I want to put lt headers on while I'm under there. Is it possible with the intake being as open as it is now the stock headers are what's causing an issue?

ghunt

Bucking right after a cold startup is actually normal, especially if you've put on a bigger throttle body. The charge motion deletes help with that but won't completely get rid of it. The cams might exacerbate the problem. Does it do it in other gears besides first?

Thomas08GT

Derf00

what is a "genavillalalala 62MM Throttle body"?? If it's not Ford, that's always my first suspect with driveability concerns like bucking, idle, etc.

Did you have the mods all done at once or over a few months? At what point did the problem start?

flash_xx

Mine did it, turned out to be the accelerator pedal. Got a new one and the problem went away. How did I arrive at that conclusion? Easy, I guessed.

Actually I figured it was the pedal because it always happened at the same spot on the pedal travel and it was cheaper than a throttle body. Turns out I was right, I opened the old one up to see what was inside and it's just a potentiometer with some bristles that run through some copper strips.

In your case, I'd try to borrow one from a friend,if the buckling goes away it was that, if it doesn't then it's the TPS, which is also not that expensive.

PS: If you can get a proper tune. My '04 GTO picked up 60HP over the tune it was running by taking it to a dyno and having it tuned by a pro. I bought it used so whatever was in there sucked big time.

flash_xx

I hope it's not Granatelli, those people suck. How they are still in business is beyond me.

Thomas08GT

First chance to open the hood back up today switched out tb for the stock one surprise it's the grantelli tb causing it. The voltage is different from the stock I called them and got a sh!tty reply of how I'm not supposed to be messing with that hopefully American muscle will take it back. And the clutch is still knocking so no connection between the bucking already have a new clutch to put in it next weekend hopefully it's Just a bad throw out