Mechanics

RATTLING WHILE ACCELERATING

2000 GMC Jimmy

2000 GMC Jimmy SLT 4x4
85,000
4.3l V6

When accelerating, I hear a rattle. It sounds like it is coming from under the hood somewhere directly in front of the driver's seat. When I let off the gas or when I am breaking, the rattle stops. It is not really loud, but definately there. I have checked my catalytic converter heat shield, and it is tight.

Thanks!
Avatar
MrKing
March 19, 2007.



There are a couple of things to look at, check to see of there is any vacuum leaks, check plugs for correct gap wires for any damage. The octane level of fuel

M_H_RITZEL
Mar 20, 2007.
To me, if it is a pinging noise I would look at the engine, but, if it is a rattling noise, I would first look at the heat shield of the exhaust manifold by the spark plugs, it may have rusted away or the bolts did, feel around with your hands on the driver side bank and see if something is loose, I had the same problem on the right bank, and thats all it was.

Tiny
Steelweels
Mar 20, 2007.
Thanks for such a quick response, guys. For anyone else wanting to offer advice, I've heard pinging/knocking before, and this is not the same. My guess is the solution will be something like the heatshield steelwheels is talking about.

I'll give that a try tonight and update.

Tiny
MrKing
Mar 20, 2007.
My mistake, whe I looked at your post I thought it could have been like a dieseling sound, steelwheels would be right, the heatshield would sound like a tin can rattling.

M_H_RITZEL
Mar 20, 2007.
Alright, checked the heat shields on the exhaust manifold. They both felt secured to me. The bolts were definately rusty, though. I didn't take the engine apart or anything, I just snaked my arm down into it. I don't know exactly what I should be feeling for, but I figured if only one side was loose, they should feel different. Both felt pretty secured though.

Any other ideas or advice for the heat shields?

Tiny
MrKing
Mar 20, 2007.
Dont know how loud the rattle is, it may still be what I mentioned, just cause they " feel" tight, doesnt meen they are, especially if bolts are rusty, in a quiet area, no noise around, tap around under the hood with a finger or something small, could be anything, but start on the driver side where you think it is, like if yours has it, it may have a protection cover or sleeve on steering shaft that is loose, and look laso at the brake dust shield on the rotor behind the tire, flywheel inspection cover underneath on tranny, re check converter and muffler shields again, driveshaft(maybe you picked up something)this can take some time to locate, or maybe you will get lucky and it will be quick.

Tiny
Steelweels
Mar 21, 2007.