So I have fixed the plenum. Checked and it's not leaking. I now run the Jegs off road Y pipe, new plugs, cap, rotor and wires. Ran the wires per the TSB, no misses or anything. The engine sounds and runs healthy as can be. Stock tire size, so it's not that...

But for some reason, there's hesitation up to 3,000 rpms, after which it runs like a raped ape. Maybe it's the tranny? I'm stumped. I should do a video of a WOT pull and post it. I can't even break the rears lose on this thing.

EDIT: I wonder if it could be a worn out timing chain... Since I need to do my water pump I'll do that at the same time.

 

What about the cat and o2 sensors?

 

O2 is the NGK and was replaced after the plenum fix. I don't have a cat anymore.

 

It revs well, right?

It might be the trans slipping until it gets moving. Make sure the level is full.

Hell, if you want to spend the money to do some digging, change the fluid, filter and tighten the bands and see what happens.

 

Yeah, revs like normal in neutral.

 

Any kind of vacuum leak?

 

Haven't looked for that. I'll check that out tonight if I get a chance. I haven't heard one, but that's not out of the realm of possibility.

 

The ones near the back of the intake manifold tend to crack often.. Check them.. Trans slipping isnt also out of the question neither like Dodge Dude said.

 

Recheck the plenum. When my plenum was blown, the truck was kinda doggy up until about 3K, then it was like someone flipped a switch to turn on the other four cylinders.....

Replaced your timing chain and gears yet? If you are over 100K miles..... it's time.