I have a knocking noise that occurs only on medium acceleration in 1st through 4th gears, cannot hear it on fifth. No unusual noises in clutch and I can rev the engine in neutral and get no knock. I can hold it at 4,000 rpm in neutral and no noise. This is where a bad rod bearing would usually rattle. I do get the usual ford oil pump rattle when starting it first thing in the morning. Drained the transmission and no metal in oil so I doubt the problem is there. No codes but the baro reading is 28.5 consistently even when the actual baro pressure is 30.1. The knocking does not sound like pinging so I do not thing i is timing related. I bought this car used and do not know the history. Is there any way to tell if it has been programmed and if so what can I do about it? How hard is it to put bearings in one of these in the car?

 

i do not know how you would be able to tell if it has been programmed, in an easy fashion. as far as replacing the bearings, the hardest part is getting everything disassembled for the bearing change.

your issue is very unique, i think that is why there have been no responses till now.

i would agree it does not sound like pinging, because you should hear that in fifth as well.

 

Thanks for the reply Hammeron. I very seldom ever get replies for some reason, may have something to do with the fact I do a lot of diagnosis before posting. I am a retired master tech so I am not new to the game. This one is strange though. It sounds like a rod but it is not consistent. I retired before the advent of variable valves so I am not all that knowledgeable on them or how the system works. I know there are some issues with the cam phasers at idle but what about around 2,000-3,500 at medium load?

 

I am new to late model Mustangs and have not even looked under my GT350. That said, do these cars have 2 piece driveshafts? My 2004 GTO had one and when the center bearing went bad, it sounded exactly like you describe. I was finally able to put it on a lift and actually see the movement in the bearing. 1 Piece aluminum driveshaft fixed it though.

 

since you are pretty sure you hear oil pump rattle at startup, i would deal with that issue first. while you have the front timing cover off, you can inspect and replace any timing components that may be worn/damaged.

 

I've never heard of an oil pump "rattling" before. The rattle you're hearing could actually be from one of the timing chains due to a worn guide. The guides require oil pressure to maintain tension on the chain and prevent rattling.
As for the knock, it sounds like it's drivetrain-related and the center bearing of the driveshaft is a good place to look first.

 

The knock is RPM related and not driveshaft related, if it were the shaft it would be faster and faster as the car sped up. This goes up and down as the engine goes through the gears. That would limit it to the engine, clutch or the input of the transmission. The chain guide may be a good thing to check, I got my oil test kit in and will be sending the oil in for analysis soon. that should give clues to what it is or isn't.

 

dont rule out the driveshaft center bearing (if its a two piece) completely, keep it in reserve. maybe you only hear the knock in first through fourth, is because there is enough torque to affect the bearing. maybe fifth does not have the torque....

 

Just throwing this out there. Cam phaser perhaps? Early 05 and 06 models were known to have issue with them that often started out as a 'tick' on startup and when cold and in certain RPM ranges...

the only contradiction I see here is that TSB specifically calls out below 1200 RPM....

http://cdn.lrsstatic.com/downloads/t...sb06-19-08.pdf

This is another one specifically about valve lash adjuster getting stuck.

https://latemodel.cachefly.net/downl...sb06-09-11.pdf