Up 'til now, for 7800 miles, I have had no problems with my Jeep. Last night, I filled the gas tank up and as I was pulling out of the gas station, I noticed I had to press the gas pedal nearly to the floor in order to get it to move. It felt like the e-brake was set, but it wasn't. Once out on the road moving about walking speed, the "drag" would release but it would shift gears very harsh (automatic trans). Even the downshifts were very harsh, felt as if I had been rear ended. Just as I got home, 4 miles from the gas station, the check engine light came on.

I thought perhaps I had not replaced the gas cap correctly, removed it and replaced it. I drove it again with the same results. Also, there is no message about the gas cap, only the CEL lit constantly.

This morning, I drove it to work with it still acting the same way.

The only other change on the vehicle other than stock is the 255/75R17 tires and wheels. I have not had the computer re-flashed to update the new tires size. I have been driving it for two weeks with the new tires without any trouble.

I was wondering if anyone on this board had any suggestions before I take to the dealer to have it looked at.

Thanks!!

Added under edit: This is the same gas station I have always purchased my gas from with no problems in the past.

 

I'd be surprised if the gas had anything to do with it. Unless it was filled with diesel or something?
I'm totally speculating but the only time I've experienced shifting symptoms like that was when the tranny was leaking and got very low on fluid. Just an idea to double check.

 

I didn't think it should have had anything to do with the gas either, but that was the only thing that happened between running fine and this. My wife did ask me if I was sure I didn't put diesel fuel in it.

I did check the transmission fluid and it hasn't leaked any.

On the drive home from work, it ran as good as it did before I put the gas in it. The CEL was still lit, but it shifted and drove just like it should. Hopefully it was a passing thing. I am planning to have the ECM flashed for the new tire size this weekend, I will bring it up with the service manager and see what he says.

Thanks for your help!

 

on my other vehicles, when the CEL comes on, i usually make sure the gas cap was closed correctly. it takes a few restarts for the CEL to reset and turn off. also, i wonder if water in the fuel will cause it to drive like the way you described.

 

perhaps it could be something silly like a loose wire, haha.

that darn electronic throttle!

 

Everything seems to be fine with it now. Yesterday, when I started it for the drive home from work, the CEL was off and it shifted and drove like it should. I guess it was just a hiccup. I wish I knew what caused this problem. If it was due to operator error, I would like to know not to do that again.

Thanks for all of the suggestions!