I took mine up a very steep loose sand (read, beach sand type sand) and had no problems with it. I would suggest you get the car checked out, perhaps there is something relating to the performance loss and the problems you are getting.

I've had no problems regarding power and climbing over anything.

 

x2

 

Wouldn't it make sense that a great deal of the problems you experienced interms of "how much power it lacks"off road were related to those you experienced when you were on the highway? In other words, the power problems were there before you went off-road and were still there afterwards.
Definitely bring it to the dealer, but be warned, they WILL re-flash your PCM once they do the diagnostic and MAY blame your problems on the aftermarket mods, especially the intake and exhaust. PCMforless will re-reflash your PCM to their specs for the cost of shipping it back to you (and you, of course will have to pay for shipping to them as well as being out a PCM while they do their thing). Why bring it it at all? Because if it turns out to be something more serious - like the head - you will be SOL and the problem will happen again. If you have the time and patience,I would put the stockintake and exhaustback on before going to the dealer so that the only thing they can blame is the PCM. They will re-flash it as I said (they did it to me before finally admitting I needed a new headon my '07). I would bring it back a week or so after the re-flash (before sending it off to PCMforless again) and ask them to throw a Tech II on just to be certain here are no new codes (such as a couple of misfires on #5).
Good luck

 

Carlos, this may be a silly question but did you put it into 4Low? I've never had issues climbing hills though I don't deal with steep sand, just steep rock and loose sand on top. H3s have a better (barely) power to weight ratio than Jeeps. Power shouldn't be an issue. Have you driven offroad before so you can compare experiences?
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It's amazing how many people take their trucks offroad for the first time and are clueless on how to run 'em. Please before you rag on the truck learn how to drive it offroad!!!! I went to Hummer's Driving Academy and there isn't one thing this H3 can't do. We drove it thru mud, sand, deep ruts, water crossing all without problems. IT Sounds like USER error not the Hummer. Read your manual or talk to someone who can tell you what each button does and when to use them. You bought a truck that can go slow over rocks, trails and sand.....but only if you know how to drive it over them.

 

Sand does rob a lot of power. But in 4 low with the tires aired down you should of been able to go anyware! I've run my tires as low as 12 lbs. with out a problemin the sand dunes at Pismo and Glamis.

 

[quote]ORIGINAL: h3carlos

I went to the local sand dunes for the 1st time in the H3, and Iam very disappointed. I have an aftermarket intake and exhaust, put the ReadyLift kit, 35" MT's, and had the pcm done by PCM 4 LESS. I never knew how much power it lacks, I had so many probs goin up hill. Finally, when I was on he highway goin home, the engine/exhaust made a weird knocking noise when I would accelerate, the check engine light turned on, and the Stability System shut off. I kept getting the service messege along with a "traction failure" messege. I ran a OnStar diag, and I was told there was a prob with the fule delivery syst, Stability system and something else. I disco'ed the battery for about an hour, and all back to norm. Drove for about 15 miles and ran a diag again, and everything seems ok. Any thoughts???? Should I still take it to the dealership to get checked out?
I still love the rig....my wife drives it about 90% of the time.

Thanks

Carlos:

The key to sand dunes an an H3 is similar to running in deep snow (without the airing down tire pressure)! Before you get into sand, AIR DOWN YOUR TIRES to 12 - 16 lbs. As soon as you tires hit sand, engage 4lock and TURN OFF the StabiliTrack System!!! Sand robs power, I've never really needed 4lowlock, but you could try it and see what you think. 35's do not help in sand, don't get me wrong guys, great tires for other stuff. You need wider tires, not taller, for floatation, not digging totraction. Momentum is also extremely important in sand, you got to get moving, keep it moving, and MASH the gas!

If you left the StabiliTrack on??? IDK from your post (no info on that topic), you and it freaked out your system. In sand, tires NEED TO SPIN AT DIFFERENT SPEED!!! Nature of the beast, StabiliTrack trys to shift the power from a spining wheel to a non spining wheel instantaneously, constatntly, but the problem is, all of them are spinning at different speeds assuming you are at least on the throttle.

Your mods aren't gonna do **** to your warranty. Leave it all on an take it to the dealer if you have ANY further problem. I have all the stuff you have, but 33s instead of 35s. My 3 goes anywhere I want in the sand. [8D][8D]








Go back and try it again, the right way and you'll have a blast! Buy a mini compressor to air back up for the dirt/road.

 

Damn Tray, Thanks....I guess. I have plenty of off road experience, I also own an 03 Silverado Z71 that is tricked out for off road use, and have never had any probs with it on any type of terrain.
HummerBob, you are too funny but you may be on to something.
Thanks for the help guys!

 

Doc, thanks for the honest and true answer to the topic. I didi turn ths Stab syst off, and the eror mssg came on a couple of minutes after I hit the highway. And, yes, tires were aired down and 4lock was engaged. It seamed that the MT's were a bit too aggresive on the sand. Once again, thanks Doc!

 

Carlos, one last point of interest to me........do you have a Base; Adventure; Lux; or the Lux w/ offroad Adventure Pkg in your 3. Mine is an Adventure so the Transfer Case is a little lower ratio which can help in sand????? Just wondering, and I am glad I could help cover the variables.