If while going slow or from a stop I accelerate rapidly then suddenly release pressure on the throttle there is a loud noise from the engine compartment. It sounds like it is coming from the air intake area, maybe like a valve is slamming shut and causing the engine to choke. If I release the throttle slowly with no load on the engine this does not happen. Any ideas?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>

 

Sounds like "turbo fart". That's a normal sound, particularly on a cold engine, although it is louder if you have an aftermarket cold air intake. Because these engines do not have a waste gate, excess boost pressure can backflow when you let off the throttle suddenly.

 

Thanks for the response, sounds reasonable but I never noticed it before and now I hear it regularly.

 

Do you have the original Ford air intake?

 

Yes but I replaced the filter with a K and N filter.