i know there is prob too many reasons for this but i'm thowing it out anyways

2007 LT with the 2.2 6800 miles

going about 55 or so ,I accelerate to climb a hill or grade, but not enough to make it downshift, it starts to surge . i can make it down shift it will quit surging for a bit. but will start surging if i hold it in "passing gear"

it won't do it with the cruise on flat ground or just driving on flat , i have to pull a hill and make it lug

 

Not sure what you mean by “surging” but here is my uneducated guess, when under load (lugging) the engine ignition system has to work the hardest and that is when any potential defects will show up (a misfire). I looked for the tread and ran out of patience but the 2007 (or was it the 2008) 2.2 had a change to one coil per spark plug. It is very low mileage for it but I would guess that one coil or plug wire is breaking down (think space shuttle fuel gauges).

 

Mine does the same thing sometimes. I read somewhere that it is probably the gas in the tank sloshing back and forth like the baffles in there were poorly designed. Just press the pedal and go. Heck with it. If it breaks down, make Chevy fix it under the powertrain warranty.

 

I wonder if there are any baffles in the tank at all the way you can hear the gas slosh around at times!

 

with a 1/2 tank of gas i boubt it could be starving the pump. any lttle bit of a grade and i could make it surge/stumble

 

My 2007 surges from 1/4 tank on down. Fill it up and the surging stops. Usually surges when slowly picking up speed shifting into 3rd gear on a automatic.

 

Is it surging enough to make you rock back and forth in your seat? Or, is it less severe? This is just a guess, but I would suggest the torque converter locking and unlocking.

 

Try puting the trans in I drive it keeps the torque converter form locking in so easy. I use it when in town or playing on the back roads

 

Thanks for the reply. The surging won't make you rock back and forth in your seat. In fact the wife doesn't even notice it. Just a gentle surge 2 or 3 times and then it's fine.

Why would it only happen when the tank is 1/4 or less if it is the torque converter>

 

Sorry lockcop, I was responding the original post, should've quoted it in mine.

Just comparing what you've stated with yours, I can only compare it to an experience I had with a truck a few years ago. It would surge with 1/4 tank and eventually the truck would shut down. Turned out to be a bad fuel pump, it was over heating when the tank was 1/4 full or less.