Very frustrated, got a 2007 Hummer H2 SUT, its a great truck, a tank for sure and to me worth every dime I spent, I live in Texas so its in great shape not being exposed to harsh weather, its my daily driver and other than routine maintenance it has not been an issue but now its an everyday problem I just don't know when its going to begin, Could start fine, run fine or Could start fine, cold or hot it will idle fine at about 500 rpm, then will miss and stall, stalls at idle/ take off from lights & stop signs and its very Hard to restart, I have to hold pedal to floor and after much cranking it will start, sometimes it will catch, idle like sh*t for a sec or two then die again, as I continue to restart it eventually it will start and at least stay alive, most times to avoid issue at lights or stops ill hold pedal to idle at about 1000rpm in neutral then shift to drive and most times that works, sometimes when it starts to idle rough I can keep alive by holding gas pedal to a high idle and other times that doesn't work it stalls....this is all with no check engine light and no codes on scanner??? very frustrated, in last 12 months I have replaced fuel pump, plugs, wires, ignition switch, mass air flow, an O2 sensor, cleaned throttle body, and replaced oil pressure sending unit and its filter screen. it was recently throwing transmission codes P2761, P0740, P0753, P0758, P0785 but thanks to this forum got that resolved, all of those codes was due to bad ignition switch and I replaced it and that solved all those codes and check engine light turned off..
does anyone have an ideas?? timing issue? hard to believe it runs this way aand no check engine light... please help.

 

Sounds like it could be the the Crankshaft position sensor or connector issue...

 

check your intake for air leaks. if you have a scanner with live data look at the maf reading and also look at your long and short fuel trim readings.

 

Will do in AM Thanks, Ill report back what I get

 

cam position sensor? might be.. ill check it out and report..

Thanks

 

Hi, ours started acting up, so i put in 2 cans of sea- foam in the gas tank, and about 30 miles later it was running like new again, so evey month i add a can of sea-foam in both h2/h3 have had no running/starting issues after that…..

 

Have you had a crankshaft relearn done? That is what I would suggest as the next step.