1998 F-150
5.4L
92,000 miles

I searched around on here a ton but can't seem to find the solution...
Yesterday the truck was fine, today i start it and the engine is growling. Neutral, Idle and in drive. As gas is applied the chugging gets heavier. It sounds like a Harley or a big diesel truck. When driven there doesnt seem to be any loss in performance. Also I can put my hand in front of the exhaust pipe exit while the truck is running and it is not very hot (not much air coming out i dont think (never tried it before so dont know if its high or low exhaust coming out))
I am nervous to drive it. I havn't even looked at the engine. (not sure what to look for, plugs, exhaust manifold?)
Anyone have advice or experience with this problem?

Chris

 

It sort of sounds like something fell apart on your exhaust. A plug that blows out will also make that sound, but you would have a definite miss and loss of performance. The one way valve on your air pump may also have gone bad, but that should sound loudest under the hood. Start out by chalking the wheels (for safety), and crawling under it while it is running (driving the truck up on ramps helps) with a flash light. Feel around the exhaust for leaks, and look for anything broken or loose. Good luck.