sticky bigblock tbi

[bigblockdually]

hey guys i was wondering if you could help me out with my tbi on my 87 7.4L. Alright heres the problem the flaps in the tbi rub against the walls of the throttle body. when the engine is cold the gas pedal is nice and easy to push down just like it should be. but when it heats up the flaps start sticking and you cant just ease into it around corners or from a stop you have to mash it for the pedal to even move but once it goes down about an inch it moves freely its just frustrating trying to drive it because you have to fight with the pedal the whole time. its not the cable because i disconnected it from the tbi and it moved in and out as free as anything but when i opened the flaps by hand with the engiune of you can see and hear them scraping until they move to a certain point then works fine so i was wondering if maybe they make a bushing kit or if there is another way to resolve this or do i have to buy another tbi unit thanks