Car: 2007 Chrysler 300C SRT8 Met Steel Blue
Join Date: Jan 2012
Location: Calif Bay Area
Thanked 6 Times in 6 Posts
There has been a lot of excellent suggestions thrown at you so I will add a few more
*Sticking PCV valve
*EGR valve going bad
*Throttle Positioner needs recalibrated
If at anytime you have overfilled the gas tank then there is a good possibility that you have damaged the Evap System. Next time you need gas, only fill to 3/4 full and see if that makes a diff.
Also see if the "surge" goes away (temp) if you downshift or drive in 4th gear at the "surge" speed. Keeping the tranny from going to 5th gear will keep the MDS from activating.
Keep us posted on your progress.
6.1 HEMI SRT8 300 and C you later!!!