Okay this is pre-detonation or pinging. A dirty MAF sensor can cause this, low octane fuel, carbon build up on the head or a pcm upgrade may be needed are the most common things on the ford. Dirty MAF being the most common.
The ignition in the combustion chamber happens to early is the cause of the noise.
There is a cleaning procedure for the MAF on this site and is where I would start. I can locate it if you can't find it."How to service" is where it is at I think.
Bumping up the octane may help also.
Tuesday, July 21st, 2009 AT 8:05 PM