Help! "Chattering" coming from passenger's side of engine.

[StangIt #1]

Over the past week, I've noticed a substantial "chattering" sound emanating from the passenger's side of the engine. By listening closely, it almost sounds like it originates from under the valve cover. I thought maybe it was detonation, but it is even present at idle (I've always noticed chatter under acceleration on steep hills, so I run 89 octane to lessen the pinging). It could also be coming from the alternator (maybe worn bearings), but I'm almost certain that it's coming from the engine. The car doesn't have a miss, there isn't a power loss, and the chatter increases when I bump the throttle. What could be wrong?

 

[NFCStang]

Over the past week, I've noticed a substantial "chattering" sound emanating from the passenger's side of the engine. By listening closely, it almost sounds like it originates from under the valve cover. I thought maybe it was detonation, but it is even present at idle (I've always noticed chatter under acceleration on steep hills, so I run 89 octane to lessen the pinging). It could also be coming from the alternator (maybe worn bearings), but I'm almost certain that it's coming from the engine. The car doesn't have a miss, there isn't a power loss, and the chatter increases when I bump the throttle. What could be wrong?

There was a TSB for a valve guide issue with the 99+ 4.6. Had some of the same symptoms.

Wonder if you have the same problems, but your's isn't covered under it.

 

[StangIt #1]

There was a TSB for a valve guide issue with the 99+ 4.6. Had some of the same symptoms.

Wonder if you have the same problems, but your's isn't covered under it.

Yeah, I just discovered a technical service bulletin from Ford for the '01-04's, but not for the pre-'99's (if you're talking about Bulletin # T-31604). I wonder if they would do anything to help me, if it does turn out to be the same problem?

 

[tomustang]

Maybe it's the recording of the tape you did of the ferrari exhaust sound

 

[Kilgore Trout]

This could be a loose plug geeting ready to blow out of the head. You should check your plugs for 12-17 foot pound torque.

 

[GDawg]

I had the same thing happen to my '98. I first thought my timing belt had jumped. I took it to Ford and they said my crankcase pully was loose and needed replacement. After they replaced it, no more clattering.