I have a 97 ram 1500 318, 3.55 gears, 5 speed tranny, 146,000 miles. Well one day it will beat my dads truck which is exactly the same except 3.92s and the motor has 10k on it. then the next it seems like its a V6 under the hood. I have no CEL's, no misses, no weird sounds. I don't have any tuners or mods just the stock 318. Has anybody else had this problem

Ever check the plenum?

Yeah, it's not leaking

Just curious, how did you check it?

Looked down thru the throttle body with a flashlight

That's what I thought.

Is there any other way without pulling the intake?

Yea, remove the TB itself and look around inside with a small mirror and a flashlight. I know it's a long one, but have you read the plenum thread/stickie at the top of the forum?

A leakdown test or at least a compression check will also help find the source of this. It would not be advantageous to put in performance parts if it is a low compression engine, first need a rebuild if that is the case.

I agree 9 times out of 10 its the plenum leaking. My truck only has 75000 miles and it was leaking like an sob. My 5.9 felt like a 1.9.