hello all. i have a 2008 hhr 2.4 50,000 miles on it. everything runs ok but at 35 mph it surges forward while running a steady speed. you can watch the rpm gauge go up 200 to 300 rpms. no lights on the dash for problems such as check engine etc, gas mileage is ok, around 25 mpg city. changed spark plugs (ac delco) cleaned maf sensor, ran out a tank of gas with sea foam in it, it still surges. anyone else had the same problem and if so, what was the fix? p.s. i park in the same spot every day and see no leaks on the pavement.
thanks.

 

More than likely it's the TCM that needs the TAP reset. There are lots of posts about this. My 08 does it all the time, dealer cant seem to fix it. I have 44k on mine, it's bucked and surged since about one month old.