After the tune up (providing it didnt work) could a fuel filter that is stopping up or dirty injectors be the problem?

 

What are the rpms at top speed?

 

My 1500 with 318 & 3.55 gears with 30.6 inch tires will do 114 in 3rd.
Just over 4300 RPM.
O/D is so high geared it probably won't do that in 4th.

 

bout 2 1/2. It doesnt go to a higher rpm in 4th even with the pedal to the floor

 

Correction, in 3rd

 

Possible transmission issue?? If it was motor you would think it should run like crap all the time

 

I dont think so. Trans works fine in normal driving. It could be a throttle thing. idk

 

Did you check if accelerator cable isn't stretched out or somehow not opening throttle fully. Have someone press gas pedal while you observe throttle lever movement with engine off. Does it ping,rattle or misfire bad at top end?

 

That sounds real similar to a clogged cat, but you apparently don't have cats anymore

 

Aint checked the cable yet but will do. Its got a aftermarket hand throttle from the fire department that owned it before me and I've been suspecting that it might be adjusted low or something.