Ok guys I am going crazy, I have a 93 K5. Has a vortech 5.7 with TBI. It is running like crap/It seems like its stuttering if thats understandable. You mash the gas it has no hesitation. Setting at stop sign or light and push gas normal and it acts like its about to die, sometims even shifts hard from 1st to 2nd....HELP PLEASE.

What I have done:
1)change plugs and wires (AC DELCO wires and plugs,double platinum)
2)cap and rotor ac delco
3)fuel filter ac delco
4)new t stat and gasket, had a small leak
5)cleaned egr, all tubes, new gasket (followed thread from here)
6)cleaned PCV valve
7)cleaned TB
8)cleaned line from brakes to TB
9) I have checked everything that has vacuum that could would or should leak.

Could this be a timing issue, any advice or insight would be awesome. I am pulling my hair out. I just bought this truck.

 

Have you checked for vacuum leaks?

 

Yes Sir, I forgot to add that, I have checked everything that has vacuum that could would or should leak.

 

Including the throttle body base gasket? These are known to leak on the TBI engines.

 

No Sir, not the TB gasket, is that something I should just change or is there a way to checkit to see where it might be leaking?
By the way Thanks

 

You can check it with an unlit propane torch. With the engine running, trace around the base of the throttle body with the torch flowing gas, but not lit. If the engine RPMs pick up, then you have a vacuum leak in that location.

The gasket is pretty cheap.

 

Thank you Sir I will check this this afternoon and go ahead and pick up a gasket. Also should there be a gasket on bottom side of breather going to TB ring? There isnt oneso just curious.

 

I am not sure what you mean by "bottom side of the breather going to the TB ring"... I do not know what you are describing. If you are describing where the air cleaner seals against the top of the throttle body, then yes, there should be a gasket there as well, but that would not cause your problems.

 

Ok sir, I checked with propane torch and no leaks. I am lost.
"If you are describing where the air cleaner seals against the top of the throttle body", thats what I was describing sorry. Would a CAT going bad cause this, O2 sensor, knock sensor? Is it a timing issue? Thanks for the help.

 

well I changed the o2 sensor, added high flow cat, super 44 flows . I took it to GM and they believe that the hesitation is due to the cam being a little to big for an injected motor. They explained it like a carb. loading up and bogging down then taking off. I also filled up with 93 octane gase and lucas octane booster. To those with the knowlege does this sound right or are they off at GM?