I need some help figuring out what is wrong with my truck. Ok when i first start it it runs good then about 5 minutes later it starts acting like its running on 1 or 2 cylinders and back fires the whole time and finally it dies and wont start till it cools down. When i drive it down the highway and it starts messing up it ll jerk hard enough i almost hit my head on the dash. i already reset the computer and that didnt help. By the way, it is a 2.5 4 cylinder with a 5 speed 2001 2wd any advice would be appreciated

 

How do the spark plugs look?
I would download a copy of the FSM. (here)
I would check your timing chain for strech. (See page 1089 aka 9-60 of the manual)

 

first off it runs in the open loop. this is normal when it goes into close loop it should run the same but it does not. only thing i would recommend is changing out your 02 sensors. even if the cel is not on they might be bad.once the sensors heat up enought they tell they computer to go into closed loop .if they are shot then this will not happen.