Ok to start off here is the truck:
1998 dodge ram 1500 sport
4x4 reg cab short bed
83,000 miles(got it with 72,xxx)
5.9l gas 46re trans
3.55 gears and 315/75-16
3"body lift

The problem:
Truck runs great. As soon the tc locks in the truck starts bucking or shaking. other then that nothing is wrong. All gears **** perfect and it doesn't do it any other time. its bad and about 45 and then its not too bad until 55. let off it goes away. punch it and it goes away. turn od off and rides like a dream.

The good:
new plugs(stock champions), cap,rotor, newer msd 8.5mm wires.
plenum is fixed right.
new thermastat and antifreeze
new front wheel bearings and axle ujoints
tires balanced
balljoints ok still.

The bad:
steering compontents
stock shocks
that's about it

The ugly:
the whole outside the truck haha

No but I ran it by a trans shop and they tested it and said the trans is perfect. I have also replace the trans filter and fluid

I have been hunting this thing too long now.

 

Engine miss. Either failing crank, or cam sensor. Getting any codes? Done a compression check? Still using oil?

 

What if anything, did you do about the cat and the o2's after the plenum fix?

 

No codes and not using oil. how would I go about checking the sensors.

and I haven't done anything with o2 sensors or cat. I did plenum at abot 72,xxx. I plan on putting new cat and o2s along with full exhaust soon as I get this fixed.

 

Cat and O2's might be contributors to the problem. Try disconnecting the front O2 sensor, and removing it from the exhaust pipe. (it will be loud....) See if anything changes.

 

I didn't think the cat would cause a miss? I will try it here in a min. Seems as though y'all are sure it is a miss? could it be a fuel issue?

 

Miss could be caused by fuel issue. Check the cat like the experts say though - if you fixed the plenum you should have fixed the cat. Blown plenum is recipe for cat problems.

 

I under stand it needs to be done. removing the o2 sensor did nothing. if anything it ran worse.

 

also just regapped plugs and checked them. all is good.checked cap terminals and theey are all tight. still no cel even after running 5 miles with o2 taken out.

forgot to mention I am running just a cat no muffler

seems to me like the bucking has gotten worse from the time it started. after it started I replaced plugs. and cleaned capand rotor

 

Did you remove the sensor from the pipe or just unplug it?