truck is not running right it would start to hesitate then right before it quit it would go about 20mph we put a new fuel pump on it because fuel pressure was low new fuel filter. did not change the running of truck so we tuned it up new plugs, wires cap& rotor even went and got another distrubtor nothing changed. pulled plugs back out to check them and the back to cyclinders are not firing. the truck has over 200,000 miles on it could this be a timing issue or did anyone on here run into this problem? or is the motor just wore out with that many miles on it it is the 4.3 vortec with tbi thanks for any ansewers

 

If it was taken care of, it should still be good for many more miles. Are you getting a check engine light?

 

oil changed every 2500-3000 miles no not getting a check engine light it will barely idle

 

does anyone else have an ides what would cause this?