so my 91 ex cab moans loudly whenever i start it. it lasts for 30 to 45 seconds and then goes away. it seems to be coming from the back of the cab/truck and i can not hear it outside the truck. but in the cab it is loud, any ideas? anyone else have this issue?

thanks
sean

 

...

soooo many jokes that could be made...


auto or man? and is this noise at idle or driving??

 

I guess you could say you "turn your truck on"

 

Dirty minds... oh crap thats what I was thinking

 

Do you have like a sub or amp in the rear of the cab?

 

auto 3.0 has a pos stereo with only speakers in the front. only thing i have done is a new fuel pump lately, could that be making the noise? it sounds like there is a ghost in the back of the truck. only at idle on startup before you move.

 

fuel pump vibrating on something?

Lots of jokes to be made here!!

 

Sounds like you def left somethin loose relating to your pump. Is your exhaust loose?

 

Any chance the moaning is coming from the rear of the engine on the passenger side? (Lift the hood, use a paper-towel tube as a stethoscope). If so, I would guess it's the PAIR valve. More than one on this list has reported that one or more of the four screws holding it together loosened up, which will cause a) moaning b) that is present for 30sec-3min after starting.

If that's your problem, it isn't tooooo hard to fix, at least if you have small hands and a very short phillips screw driver.

 

The PAIR valve could be a culprit- it's basically a pair of reed valves and it's possible that they are oscillating causing a moaning like noise.
But being you can't hear it outside the truck it's likely something in the fuel system- the pump or something connected, oscillating. Maybe even the fuel filter has some air in it and it's taking a bit to get the air out. Could even be the fuel pressure regulator.
If it were the 22re and a little older, I'd suspect the pulsation dampener but I don't believe the V6 has one.

 

pulsation dampner sounds dirty...