Ok, let me rephrase:
When I start my truck, it will only start at half throttle and won't idle or drive. When I run WOT, the throttle pulses and goes no where. The throttle respondsnormallywhile the truck isn't running
Ok something happened, I was replying and it all got erased. I'll try again: As long as you are sure it works 100% with the engine off then it's time to look for loose metal. Make sure your pipe and header aren't vibrating together and look for loose screws. Anytime you have metal to metal contact or a loose washer or screw dancing around it can cause radio interference. If that doesn't help then it's time to check out the engine. Change the fuel tubing and plug, look it over for any place where it may have been dumping fuel. Does it sound like it normally would? I've had crank bearings go bad on 3.3's that made them run terrible, but never screwed with the radio. If all of the above checks out and you still have a problem then you may have an air leak. Also make sure the steering works normally with the engine running. Get back to us if all this stuff checks out.