Help with 2.7 ~ Throttle issues

Can any one help me out I got a 96 2.7 how come it won't go full throttle and it falls flat on it face at 50 and I can only gice it qauter throttle but if I turn the truck off and turn it back on it runs really good then starts to run like shit after like 30 seconds. Any help is helpful thanks

 

throttle position sensor bad?

 

Catalytic converter. Undo the pipe in front and see if it still does it.

I worked on a Dodge Dakota that did that. I was the grunt that changed 2 motors in it.

 

Truck is in limp mode.

 

I don't have a cat I got it straight piped from the header to a flow master. Ok any one no how to get it out of limp mode

 

Try to disconnect the battery for a few minutes. Are there any other driveability concerns or issues? Up until the throttle problem,how was it running?