Hello all,

I am at wits end about what is causing the stumble. The rig has 60,050 miles. I have replace the intake manifold gasket at 48,000, replaced plugs with ngk, new fuel filter, put in additives to remove water ( if any in there). I even replaced the muffler in cause it was too free flowing. The symptoms are taking off from the light it stubles, almost sounding like a vw bettle. Also at highway speeds it surges. Any other thoughts or possible causes would greatly be appreciated.

Adam 2003 chevy suburban 5.3 4x4
1989 chevy suburban 350 v-8 4x4 - superwinch hubs-(sold)
(sold) 95.5 Rodeo S 3.2 4x4 - K&N drop-in,2.5in lift, 31x10.50r15 wild country txr,superwinch manual hubs