knocking noise

[willdo]

2004 grand prix 3.8 engine knocking noise thought maybe rocker arm stud then maybeflex plate

 

[Fivefingerdeathpunch]

That isn't enough to go off of, more details are needed.

Is it all the time?

Rise and fall with RPM?

Glitter in the oil?

Have a video?

 

[FordMan77]

Canooter valve for sure. Pretty common.

 

[01Blackgtp]

Knocking in the bottom end, cold, warm, idle.


Need some more details...

 

[GTPpower]

It's most likely your dog's tail hitting the door when you say "good dog."

 

[willdo]

2004 grand prix 3.8 engine knocking noise thought maybe rocker arm stud then maybe flex plate

Sorry wasnt done my wife sent anyway noise is all the time ive been a mechanic for 25years the only thing ive ever ran into like this turned out to be harmonic balancer was just running it past you guys who have been around these vehicles and idont have a dog , have only had a week was given car front valve cover off no pulled studs going after balancer

 

[Scottydoggs]

with a vid we can pretty much tell most time accurately what it is. we've heard it all from rockers to bottom ends to flex plates.

do the old hold it at 2500 rpm and let it drop to idle, we're listening for the rod to be knocking on the fall of rpms, you kinda hear it bounce to its own beat.

top end you get a misfire code sooner or later, but they stay in rhythm during that test.

flex plates tend to knock at idle and go away driving some times. depends on how broken it is. sadly stock set ups break em. dont even need to be abusive either it seems.