Traverse Chevy 2009 missing especially uphill on gentle grades

I’ve taken my Traverse in to the shop twice now and they can’t seem to find the problem - it misses going up gentle grades,

especially when on cruise control and higher speeds.

First they said timing belt, then spark plug wire, but it’s happening

again and I’m about to take it back in. The last time they test drove it and they said they couldn’t duplicate the symptoms but I think they didn’t take it out for long enough of a test. Anyone out there have a Traverse that misses going up gentle grade?

I’m really curious about who might have told you that the problem was related to a timing belt.
A timing belt would not be related to this type of problem–if your vehicle had one.
To the best of my knowledge, this engine utilizes a timing chain, rather than a timing belt, so I suggest that you stop taking advice from whoever gave you that information!

The problem might be related to fouled spark plugs, or to a clogged fuel filter, or to a weak/failing fuel pump, or…

If, as I suspect, this vehicle is still covered by the Powertrain Warranty, then you don’t need a diagnosis from us.
All you need is a competent dealership to find and rectify the problem. A different Chevy dealer should be considered as your next stop at this point.

You also might want to contact GM at the corporate level. Contact info can be found in your Owner’s Manual.

I would actually also be worried about a torque converter lockup problem. The transmissions in these vehicles have chronic problems, even at low miles, with various transmission control solenoids. Does it have a tachometer? As this behavior happens is the tach bouncing a bit - maybe 2-500 rpms as it seems to miss?

How many miles are on it and what has the service history of the transmission been?

I’m not saying that’s it. Just that it should be added to the realm of possibilities along with fuel pressure, spark plugs, etc.

My faulty VCD driver, I meant timing chain, not timing belt.
I do think it must be fouled spark plug or spark plug wire.
It is still under warranty. I think I’ll take your advice and
ask for a diagnosis from another dealer. Thanks much.

Thanks for the tips. I am going to watch the tachometer now and see what it does.
There are only about 22,000 mi on the car right now. I otherwise like the car.