I've been noticing a slight hesitation when accelerating hard..towards end of gear it's getting worse and also during gradual uphill driving at highway speeds..Fuel Pressure regulator has just been replaced and has made it slightly better..my mechanic diagnosed it as the regulator..100k miles now...i changed the fuel filter 3k miles ago..new injectors ...AIC replaced 8k miles ago...not sure what else it could be..any suggestions would be helpful...it feels like it's not getting enough fuel or air possibly...mechanic said fuel pressure in high revs was bouncing from 40-65....

thanks..GPyles

 

forgot to give specs....vehicle is a 5.0L 302cid w/ AWD

 

Maybe the cat coverter? Does it run any better/worse when the engine is hot?

 

No..it seems pretty consistent..