It very well could torque converter shudder.

 

I understand what yall are saying but my problem is that it does aruond 1500 rpms when it shifts in i think 4 forth gear it will stop when u go faster or slow up.

 

You need to check the plenum and the cat(s) as previously stated.

 

I will check the cat but y does it only do it at one speed and not at all the time if the cats are the problem wont it do it all the timw? what am i looking for on the plenum?

 

Did you read the plenum thread ? You may very well have a tranny problem , but a loss in power, even if you don't notice it, can possibly cause that issue also.

 

Can i check the cat with a heat gun and get a good reading?what temp should it be?

 

Unscrew the pre-cat O2 sensor, and see if the truck drives better.

Or:

Get the appropriate gauge, drill a small hole in the exhaust, right before the cat, and see what the pressure is at idle. (over 2 pounds is too much)

What happens is, if you have a miss, you may or may not notice it until tcc locks, at which point, you have a direct mechanical connection from engine to trans. Makes any running problem far more apparent. Mine did this too.... when TCC locked, I thought the whole truck was going to shake itself apart...... fixed my reversed plug wires.... and it was happy again.

 

You might be able to rent the gauge setup, and it should have an adapter to screw into the o2 sensor bung. No drilling required.

 

Pulled the O2 sensor out and the truck ran the same no difference, only louder. I put the O2 sensor back in and pulled the breather off - it has a steel plenum - did notice something different while the truck idols - it has a low end skip or a small vibration - so i don't think its driveline unless it is two different problems. Anyone?

 

Fix the miss, see if the other problem goes away.