bog/ miss fire under heavy acceleration

[felskee]

i have a 99 5.7 vortec and under heavy acceleration ONLY WHEN WARMED UP bogs, missfires it sounds like then catches up in the higher rpms. almost sounds like a 6 cylinder then goes back to normal. when its cold it acts like it should. its a fairly new motor( rebuilt withing the last 50,000. new spider and replaced the distributor gear so im kinda stumped on it. i have p0327 knock sensor come on every so often and p0137 which is the 02 sensor by the cats not the important one. im left to think its the knock sensor possibly. does any one have any insight on this?

 

[munly]

Did you check the cam retard...?

 

[felskee]

i thought the cam retard would throw a code?

 

[98_k1500]

Mine did not, and my cam retard was on -45°. can definitely cause this.

 

[Case182]

My '97 vortec is doing this too. Just the bogging down part though. It's only doing it on hard acceleration from a stop. It'll big out when it tries to grab the next gears or a few seconds, and then pick back up like nothing happened.

 

[felskee]

where would you go to get this fixed? dealership? i know you have to have a scan tool