Does it bog down like it has no power, or does the engine stumble? Could be an EGR problem. Disconnect the vacuum hose from the EGR valve and drive it and see if the problem goes away (the check engine light will come on until you reconnect it).

 

All that needed to be done was to clean out the EGR Valve Ports. Total was like $250 for diagnosis and labor. Not to bad.

 

Could have done it yourself for free...

 

:nono: :upset: STEALERSHIP BRO STEALERSHIP:upset::nono: