Mitsuibishi Endeavor Misfires – 2007 | 82K

2007 Endeavor LS AWD – 82k Miles

I recently had both check engine and tcl lights come on solid a day after a 65 mile trip through rain ice, and bad weather. Accompanying these lights on is a rough idle at low idling rpm’s and vehicle shaking at higher ones when I tried to drive it. There is 1/2 tank of 91 gas and the gas cap is locked tight. I checked the oil and it was fine, I added fuel injector cleaner along with dry gas and ran the vehicle about 15 miles. None of this seemed to help. I took the vehicle to Autozone and had them read the error code for me which was P0300. The autozone person further said it was a Cyl #4 misfire. I took the vehicle to a repair shop and they ran a diagnostic. They confirmed a cyl #4 misfire (P0304  I believe). They proceeded to change out the coil on cyl #4 and a new error code showed up identifying a misfire in cyl. #6. They checked all the plugs and wires and found no problems. There was no evidence of a manifold gasket leak either. The timing belt on the vehicle has not yet been changed. After this they stopped and said I should take it to a dealer who has better diagnostics to identify the problem since they didn’t have the ability to further investigate the computer diagnostics. They said it would require Mitsubishi to do so. They did not charge me. The vehicle is running considerably worse after their attempt. It barely idles, engine shakes, and seems like it is running on 2 cylinders – hardly any power.  I am concerned about what could be wrong. I have read a lot and seems like most of the usual suspects have been eliminated as the cause of the issue. Any help before I take this to a dealer would be greatly appreciated.