My 5.2 has roughly 90,000 miles on it. i notice that when it warms up there is a weird knocking noise, it almost sounds like a flapping noise that comes from more on passenger side of the motor. I notice it more inside the cab than outside. When its cold it doesn't do it, only when it warms up. any ideas?

 

Do you hear this under the hood only, inside the passenger compartment only or both?

 

I have a 2001 5.9 and hear a noise too only when warms up. It is hard to hear under the hood but can hear good in passenger compartment.No clue where it is coming from.

 

I can really only hear it from inside the vehicle on the passenger side, its weird because as soon as I turn off the truck and then start it right up it takes about 10-20 seconds for it to start back up!

 

i think what you are hearingis coming from the fan motor by the passenger feet area. i ve noticed this two in other cars but im not sure whatcauses it. find the answer and post it let us know

 

what you are describing sounds like a evap purge solonid. what year is your truck.

 

Its a 1999, what is this solenoid thing?

 

mines a 2001 5.9 and just tried again to find sound listened all over in the engine compartment and below could not hear nothing. but when I climb in the cab I hear it. Clickety-clickety-click-click-click-knock-knock-knock.

 

ballbeerfish, try putting your hand on the floor on the drivers side floor, to the left of the brake peddle. tell me if you can feel it in the floor. i think im having the same prob.

 

ohhhh... i thought you were talkin about knock knock click click clickety clack..



sorry had to.