Bucking at part throttle

[FordRacing302]

I have an 89 GT with an F cam, full exhaust and full MSD ignition, other than that its pretty much stock...At lower rpms (under 3000) when I try to cruise at part throttle the car starts bucking and hesitating, just wondering what could cause this.....BTW my brake booster is shot and leaking I dont know if that would have anything to do with it

 

[jka]

Could be the cam duration if you are running a 5-speed or you could be runing rich or you could have the tps set to high for the idle speed that you are runing. See if you set your idle speed low and your tps high you are going to have problems.For example when i installed the cam in my gt i had an idle speed of 800 rpm and the tps was set at 0.97 and when i drove it the it was bucking at cruise. But when i lower the tps to 0.82 and adjusted the idle to 900 rpm it was fine.You don't really need to turn the tps up high to get good throttle response because the computer will adjust and you will have good throttle response at 0.82 and less bucking.Try it good luck.

 

[FordRacing302]

I just tested the TPS and its reading 4.9V closed throttle all the way to open, so Im guessing my TPS is bad

 

[liljoe07]

Possibly, or you have a wiring problem, or problem with the computer. Try just testing the black wire of the TPS to a ground. See what the voltage reads. May also want to try and run the Key on, engine off codes also.

 

[FordRacing302]

I just replaced the TPS and it runs a whole lot better, its idling high now (1200RPMS) but before it would alternate between 800 and 1400 so Im guessing I just need to adjust the idle oh and the gas smell is gone

 

[jka]

Set your tps from .080 -0.90 and set the idle to 900rpm because you're running the F-cam and you will be good to go