I'm having trouble with my 03 H2.

I did a rev (not to redline, and I had just made about 25miles on the truck) just so a friend could see the sound the exhaust makes, because he is putting one like mine, and just after that, when I accelerated normally to continue my journey, the truck was responding to the acceleration very badly.
Since there was a parking where I was, I just turned off the engine, and waited for about half an hour, hoping everything would be ok.

I started the car then, and everything was ok, I did a few miles on it, probably around 10 or so, and after a while I got on the highway to go home, and the engine light started blinking, and the car started to slow down, and to not respond to the acceleration like it should.

I couldn't get good speeds, the exhaust made the usual sound it makes, for shifting gears and everything, but the car just wouldn't get to the speed it should. I pulled over, turned off the engine waited a couple of minutes, started the car again, everything seemed fine for a few seconds, but then the same thing started to happen. I made about 10miles on the highway like this, made about 5 stops, turning the ignition on and off, but it got to a time, that when I turned on the engine, the truck would star shaking a lot, there was really a lot of vibration going on, and it started to get only speeds of about 20-30mph max. Then at about the 3rd stop I made, a little hissing sound started happening, it came from the engine.

Temperatures were fine, exhaust sounded like usual, but the car just wouldn't respond like it should to the accelerations.
On the 5th and last stop, the truck started to smell a lot like gas inside, that's when I decided to just quit, and call a tow truck. I was about 3miles from my exit on the highway, but I decided not to force the truck anymore.

I have it in a mechanic right now since yesterday. He thought the problem would be from the spark plugs, but he changed them and the problem persists. Actually, the hissing sound started to get higher now (first it only happen when I used the gas pedal, now it does with the engine on, in idle). Due to the sound being louder, it was easier to detect, and it comes from the air valve.
I found an image in google images, just so I can point out, where the hissing sound comes from in the engine:



It's not exactly there, it's a little to the back of the engine.
By taking out the hose from the air valve, the sound becomes louder, which indicates it's coming from inside. The mechanic is going to open it up and see what is making the noise, but the shop was closing so he will have to do it Saturday, since tomorrow is a national holiday.
The hissing sound comes from the air valve, but I don't think that the problem with the engine cutting off, will be related to the air valve. It's probably just a coincidence, and I got 2 problems at the same time.

By the way, I have a LPG conversion kit installed, the rest is OEM, except the exhaust. The car has the same behavior either riding on gas or LPG. (actually the LPG system is all over the engine, that is why the mechanic could not open up to see what is the problem with the air valve, there are a lot of wires in there, and he will have to unscrew and disconnect some things to get there, and today there was no time to do it).

There is no Hummer dealer in PT, these cars are actually pretty rare here so mechanics are not used to them.

If you could help, and point out possible solutions, please do.


Thanks

 

YouTube - ‪IMG 0314‬‏

Here is a video of the noise it's making, the video is not very good, but it does the job.

I'd really appreciate if anyone could help me out with this...

 

If the cel is blinking your engine is misfiring. Your pic looks like antifreeze is all over your engine? did it ever overheat?

 

That does not sound good at all....die remove the belt & see if the noise is still there....sounds like a bad h20 pump? would explain the antifreeze

 

Just reread your post pic is not your truck...lol disregard my posts sorry

 

Lol no prob

 

I would like to know if the issues addressed in Hummer H2 trouble, engine cuts out posted in 09 was ever solved because a friend of mine is experiencing the same problems highlighted and am looking for any possible solutions. thanks