Hi Guys

New to the forum hopefully maybe someone can help

i have a 2000 GMC Jimmy 4.3

When i try to accelerate hard the engine bogs, doesn't go no where, i can accelerate normally without any issues.

Complete tune has been done, not MAF, Cat has been changed,fuel pressure is fine

Any suggestions?

 

sounds like a vacuum line is either broke or disconnected. time to break out the stethascope

 

vacuum is all good

no service engine lights on

 

thats odd. i'd still check all the vacuum lines just to make sure if you havent already. did you check vacuum from the test port? could be a broken hose after the port