Would this be tune related? Fuel pump is holding pressure

5,500 RPM holding - YouTube

 

Also, it didn't do this before I installed a 3000rpm stalled converter and the new PCM for the converter. Here is a video of how it ran before the converter

Turbo 5.3L w/ 4L80E and STOCK STALL - YouTube

 

have you talked to your tuner?

 

Sounds like you have a shift command table off in your tune. You need to take to your tuner.

 

check ETC rev limiter settings.

 

****.. tuner is in san antonio, I'm 8 hours away. I sent them an email w/ video in it

could my rear tires being 1/2" taller do that? (I had a blow out a few days after I sent in my tune form.. so the info never got to them)

 

Could be low on timing and rich up there. I ran into that when i was learning how to tune my truck.

 

Tuner says PCM/tune wouldn't cause that, says that the converter also seems too loose

 

Tuning would cause that. You need to have your truck datalogged to see exactly what is happening in the PCM while the problem is happening. Sounds like a fueling problem but no way to tell without datalogging

 

Does that mean that you have about 8 psi over your base pressure at the time this happens?

I say +8 psi assuming you are boost referenced. It sure seems like a fuel supply issue to me.