Hi all,
I have a 2001 1500 with the 360 in it and I have noticed it more lately bu when I am accelerating with some load on the truck ie up hills etc the truck will make a rattling noise coming from what sounds like the left firewall mayve back of the engine. I can hear it worse when I gt a little harder on the pedal but when I get into the pedal to make the trans downshift it seems to dissapear. Please help.

What I've already checked:
1. Changed oil from 5w30 to 20w50 (it has 125k miles)
2. Checked down through the throttle body and there is no oil there.
3. The truck does not burn any oil. The dipstick doesn't indicate it anyway.
4. Filled the truck up at Chevron with 87 octane and no difference, I normally pump Arco 87. Should I try a different octane?
5. PLEASE HELP!!!!!!!!!!!!!!!!!

 

catalytic converter

 

+1...

 

sounds like spark knock (pinging)...
fill up with high octane gas and see if it goes away.
if so, there are several possible causes, including leaking plenum, carbon buildup, timing chain, any/all of the above combined with advanced timing (jet chip, hypertech)

 

If it is a leaking plenum when I look down into the throttle body, if it's not leaking what should I see? Should I just run some seafoam first to see what happens after the higher octane gas? Or before? The truck doesn't use any oil but what are the symptoms for leaking plenums?

 

I agree it is probably pinging. My buddys 360 pings like anything when the rpms go high. His sounds like a bunch of marbles in a metal coffee can getting swirled around. Thats the best way I can describe it. do just what dhvaughan said, (fill up with high octane gas and see if it goes away). If it does, then you know your engine is pinging.

 

Okay sounds like a plan, though I am going to run Seafoam from the brake booster line and see where I end up. Also I plan on changing the spark plugs.