Rebuilt my 86 f150 with a 90 5.0L in her, headers and straight bush burners! sounds awesome, heavy duty 4 speed in her... She starts perfect, and runs great, but she idles high, theres no filter on it yet though.. but when I take her out for a spin down the road, at any time if i give it gas it wants to die down first if you give it too much gas... sounds like it chokes on it self then kicks in and revs.. i need to fix this problem.. i have a 5.0 mustang motor, and i was wondering if the throttle body from it will fit on my truck, it has a single breather hole rather than 2, so i can just put one tube with a filter on it... any help is apreciated!

 

............ anything? I realized the plug on the right of the second throttle tube was unplugged... i plugged it back in and now it idles higher, but doesnt hezitate as much when you go to rev it.. i think the timing might be off, but why does it idle so high?

 

Sounds like a vacuum leak. Check all vacuum lines. Use an unlit propane torch to find any cracks in the lines by running the engine and pointing the propane on the lines and listening for a change in idle. Point it around the intake as well, a leaky gasket can cause high idle.

If that fails then grab a vacuum gauge and read this.... How to diagnose your Ford engine using a vacuum gauge