First things first,

1998 ram 1500 130k, auto
SCT 93 Octane tune ( I run 93 all the time)
180 t stat
No cat
Spectre CAI (if it makes a difference)
Plenum fix (well it was fixed..)

When I'm in heavier than normal acceleration, like getting on the highway, I notice this weird noise coming from the engine, almost as if it sounds like the fan is hitting something under there. The noise starts probably at about 2100 rpm and will last to about 3000. I would have thought to be ping, but definitely not a pingy tone, ( I know what ping sounds like when I ran 87 on the 93 tune ) I literally have no idea what it could be. Any ideas can help.

If its coorelated, when the engine is warmed up, and I'm in Drive, and slowly let off the brake without giving the truck, she shudders, now it did this ever since I got the truck with 109k on it. Brought it to the transmission shop once, thinking it was the torque converter, but was told it is the engine, but never pursued anything else.

The plenum was repaired a while back, and is again leaking, the reason why, I have no freakin clue and its driving me nuts because I'm very **** when it comes to that kind of stuff, especially torqueing bolts, anyway I have an AirGap thats hopefully going on soon to forever rid my problem. Thanks in advance.

 

If it occurs at higher torque conditions, it might be engine/transmission mounts shot.

 

I second that. Motor or transmission mounts.

 

Any way I can confirm this? Revving in park?

 

Visually inspect your mounts first, make sure the bolts are tight.

 

Give the rubber a poke... if it is soft and gummy (and/or oil covered), they're likely shot.