07 H3 went into reduced pwr, misfiring, shaking and back firing

[Happy Hummer]

07 Hummer H3
Miles: 100k ish
Symptoms: reduced pwr, shaking, mis firing, back firing, check engine light flashing

Situation:
Started truck after sitting 5hrs. (Had drove 7+miles to get to destination across town)(H3 started at my home in driveway just fine). Anyways drove to destination and went in for a number of hours. Came out to (-2deg [f.] -17deg wind chill). Proceed to start 07 H3 and it started up but went right into freaking out. Had to keep pedal depressed to keep rpm at 2200-2500+ to keep engine even running. Shook so bad and back fired I was really concerned about engine. It would die the moment i'd leave foot off pedal. Turned off and retired 4+ times. Still same stuff + extra dic msgs.
I Remembered I had cheapie code reader in back cubby. Grabbed code reader (it was frozen so bad screen was pixelated and distorted to point of slow, lag and very hard to read or function.
Even so cleared codes (there was literally NO way to navigate the menus because of missing stuff on frozen screen) and Turned truck off/key out. Put code reader away. Started H3 and it ran just as if nothing happened. Went back inside the place I was at and let it warm for quite a bit. Drove home in a meat freezer because it is that freaking cold and I could just feel and tell everything was a lil off because of the extreme temperature. Left truck run in my driveway at home and started another vehicle. Came back to try shutting 07 H3 off and restarting 4 times back to back. It started every time. No issues save maybe a bit of lag because of cold temperatures. Left idling in driveway for 20+ minutes and turned off.

So it now has me wondering what might have gone so wrong??
I've never experienced these symptoms before tonight . Ever!
Been a great vehicle.

 

[rascole]

Possibly a battery issue in the sub zero temp?

 

[alrock]

I'm thinking battery issue too. Batteries die differently in the desert - they break internally vs. fade away - and I had very similar symptoms once when it died at a convenience store. I was able to get it started with a jump but it drove similarly to what you describe on the way to the auto parts store for a new battery.

 

[Happy Hummer]

Yes. I would normally agree with battery statement and maybe it is but just got the battery in August or September this year. Vatozone gold premium.

 

[Happy Hummer]

Good suggestion though and worth considering.

 

[Happy Hummer]

Update:
2pm Sunday 121325

Just now started H3 after night of extreme cold(for us anyway) and truck started fine. No freaking out. Weird. But very good .

 

[Happy Hummer]

It got way down last night in temperature... something like -25 wind chill and -5 to -10 air temperature. For us in December this is like record settings territory.

 

[Happy Hummer]

This is the kinda cold that kills if not properly prepared. No b.s.

I belive other locals north and west of us were extreme kill ya cold air temps.

 

[Happy Hummer]

Sorry Sunday 121425

 

[woodwardsh3]

You may have some water in the gas that froze near the pickup. Try some dry gas or Heat in the red or yellow bottle. With today's gas and ethanol, it happens.

 

[Happy Hummer]

Yes, very plausible. Thanks for the suggestion.

 

[Happy Hummer]

Well, we are back above freezing and 07 H3 thankfully has continued to start each time normally . Of course we'll be below freezing tonight and tomorrow so I'll update further if necessary.

 

[Jeepwalker]

Maybe there was some moisture in the tank and it sucked some in. Vehicles behave like you decribed when they injest water. Or the timing actuator froze and got stuck. It's at the top of the engine where moisture might accumulate. Re-freeze after sitting. 7mi might not be enough to get moisture out of the engine on a real cold day. Otherwise, hard to say.

Hopefully there won't be a next time. But if there is, try to grab codes if possible.