Hello everyone. Im seeking some assistance. I just purchased my First hummer H3 solar flare, 51K miles automatic. Love it but i think i purchased a nightmare. Upon riding home with it I discovered it had a broke Radiator. Replaced that. It has a rough idle(rpm is consistent), Motor torques when reving so Im thinking it has a broken mount somewhere. My real issue is I went WOT to pass a truck for the first time in 2nd gear and at 4,500 and 5K RPMS the needle sat for a sec or two before continuing to redline. Im thinking its a misfire but no Blinking CEL or CEL. I come from the grand prix GTP land with a modded Grand prix (runs low 12's 1/4 dynoed 320WHP, 364lftbs). The GP had issues like this related to clogged cats. Is that prevalent to these as well? I have HP tuners for my GP so i plan to run a few scans on the H3. Some things ive done so far, even though it only has 50K miles I swapped the plugs out. I also gave the TB a nice scrubbing and cleaned the maf to no avail. Also Ive noticed that 3rd gear lock up kind of feels like a slip anyone have that same issue? I love My H3 but all this has me concerned. Anyone have any thoughts? Thanks

 

one thing I should add is I don't feel any Misfires any other time and normal driving seems fine. I also ran 3 bottles of techron cleaner in the tank

 

5yrs,50000 miles, coulda been anywhere. like the dodge hemi owned by a little old lady who drove it only on weekends to church and then the dragstrip! so you have some problems.
plugs are critical. did you use oem like original?
what is 3rd gear lockup?
the book will tell you that the torque converter goes in/out of lock around 45 mph.
do some reading and searching, theres a lot of info here.
oh,these are not race cars, ive never red lined mine.

 

one last thing, Sorry lol they need an edit button I cant seem to find one. Anyways I hear a chatter at cold start from the valve train that goes away in seconds. Im hoping that's something to do with the Variable valve timing?

 

Happy, thanks for the reply Yes I went with OEM plugs.

 

We have that noise to at start up. Have since the day we got it. Goes away in a few seconds. We've put 70,000 miles on ours in just a few years with it that way.

When you cleaned the TB did you take it off of the motor or did you clean it while it was on there still? If not you have to take it off because the other side is just as dirty as the outside is.

We had a rough idle when our TB was dirty. Also had a rough idle once when one of the coil packs was cracked, and also had a rough idle when the purge valve was bad. That's not too bad of a fix and I've got a tutorial on purge valve replacement if you find that's what it is.

Clogged cat can cause erratic idle.

 

Your start up noise is probably the hydraulically actuated timing chain tensioner, normal.

Old thread with pic and diagram, my post #17. https://www.hummerforums.com/forum/h...3-21813/page2/

You have an I5, they are not inherently balance so you may "feel" like you think there is a rough idle. It would be a matter of degree and since we can't look at it or feel it, I can only assume you are like the bazillion other people on here posting the same observation not understanding what the I5 is up to. You know what assumptions are worth.

Same thing with motor torque, matter of degree, they all do it. You could have a bad MM, but you can check that out.

Your RPM observation (we ain't there to look at it) but you have a stock AT with mush for shift points, set for soccer Moms and Mall crawlers, it shifts slowly and avoids crisp quick type shifts. Soccer Moms don't spend much time at WOT, so shift lags are the name of the game. You can set those any way you like with a PCM tune.

Cats only last so long, especially when throwing too much unused fuel out the exhaust.

Lots of info here, search it out.

Welcome.

 

The edit button is in the lower right corner of your box next to the quote button.

 

to edit you need t be here a while,?? how long?

hey doc, tell me about this unbured gas,

[QUOTEthrowing too much unused fuel out the exhaust][/QUOTE]

heavy foot?

 

Thanks for the replies! Lock up referring to TC lock yes, it seems to slip when engaging in third gear. Might have to play with trans pressure and shift points alittle in HP tuners. The RpM hang feels like a hard misfire it stops pulling and hangs for a moment then continues. Almost feels like value float. But I'm surprised it doesn't flash the CeL. Regarding the idle shake It rattles the dash and I realize that odd cylinder engines are inherently unbalanced but I'm checking the mounts im sure there hydraulic filled mounts that have a high failure rate. I did not remove the TB when I cleaned it I just flipped the plate up and cleaned both sides of the plate and bore. I'll pull it this weekend if there something I could have missed by doing that.