RPMs drop to almost stall but doesnt
 

Hi folks! Bought my first Hummer. Its an 06 H3 I love this machine best ride Iv ever owned. I have a couple issues. My main concern is the rpms drop when I come to a stop almost to the point of stalling. It causes lights and heater fan to dim for a moment which is not going to be good on them in the long run. I had it into a GM mechanic who said they could not figure it out but they tryed to clean the mas airflow something, but it did not help if anything it seems a little worse.
The engine light was on and turned out to be the thermostat so they changed that but could not fix this RPM, idle issue. Anyone encounter this or have any insight to a possible solution?

Mine does the same thing. Ive cleaned everything you can clean, done the coil pack mod, new plugs, fuel injection cleaner, head and cams are new?

I would love to find a fix.

Have you all taken the throttle body completely off the truck and clean the backside of it? Mine gave this issue a little while back and actually began stalling on me. I changed the VVT solenoid and both cam positioning sensors. Spraying and cleaning the front side of the throttle body isn't good enough.

Yes, this has been talke about many times!!
Mass air and TB need to be taken out and cleaned with PROPER cleaners! They make mass air and TB ONLY spray cleaners, use them, be careful with the mass air when cleaning it!

My 07 did it, has 120k miles on it and now it purrs like new when coming to a stop.. No problems! Got to take that TB off and clean good with old tooth brush and lots of TB cleaner

Thanks for these tips guys. Im in Canada and we are having colder than normal winter. I dont have a garage to work in so ill have to get mechanic to try this.
What should excpect how much time it will take mechanic to clean throttle body, TB? He charged me $100 to clean mas air flow and now I suspect he never cleaned it fully after some posts I have read about cleaning it properly.
What is the VVT? And TB?

Hopefully that will fix the OP's problem but for me no.
I have removed and thoroughly cleaned the TB.
Cleaned the MAF with MAF cleaner.
Removed and cleaned the cam position sensor.

It does this all the time and it never trips a code??

$100 bucks for 5 minutes of work. Whoa!

Yes the TB is the Throttle Body, it is about a 20 minute job to clean it w/ TB cleaner, removal and install included. Doesn't matter how cold it is, winter hasn't even started yet. :p

Search out cleaning throttle body, there are tons of posts on this stuff.