trouble with c today :'(

So we where driving the c today when it started shaking bad so I pulled over everything seemed fine but when I started driving again the gas mileage would not go over around 40 Mpg and the regenerative braking would not charge the battery. The car continued to shake badly and the check engine light began to flash. So I called the dealer and they said to bring it in right away. So I drove 45min to the dealer it was shaking on and off the whole way the check engine light was flashing on and off the whole time. And when I got to the dealer I only had 40mpg I drove 60 mph the whole way. So now the dealer has it and I am waiting to see what happen. O yeah the car just hit 8000 miles on my way to the dealership. Has anyone else had an issue like this ?

 

Ok got it back from the dealer they said there was water in the gas. They said if I does not run right I won't charge the battery. They wanted $468 to drain the tank and flush the system. I just did not have the money to get it fixed at the dealer so I had to pay a $63 diag fee to get the car back. Went to auto zone and bought water remover made by heet. Runs fine now so I guess my question now is are these engines very sensitive to water being in the gas ? Reason I ask is cause my wife and I went to the gas station at the same time before the storm sandy and filled the c (hers) and the focus (mine) and the c acted up but mine still runs fine ???

 

Yeah it ran bad from the dealer I had to drive like 20 miles or so before it slowly started to smooth out I don't recall which one I bought I just told them what happened. They told me what I needed I remember it was made by heet but I walked out to the car poured it in tossed the bottle ( in the trash of course) and drove. It still ran bad at first but then I noticed it to slowly run better and better. The guy at autozone also said to fill it up with a high grade fuel on the next fill-up and then go back to regular. I guess I couldn'thurt for one tank then go back to 87 what do yall think?

 

I always use shell gas cause it is one of the closest name brand gas stations to me where I live (6 miles away) . First time I ever had any trouble with gas from them.
Yeah I would have recycled the bottle if they had a place around here to do so. I live in southern VA in the backwoods down in the Hollar. we take our trash to a local area, not a land fill mind you just a little cut out the county has set up near by that has 3 or 4 dumpsters that we throw everything in to, no recycling dumpster at all. It won't be long tho another couple of years they will.