Rough Idle & Flashing CEL

[duke16]

yes.
I've been running high grade exclusively for the past 2.5 weeks because the car seems to run better and i get better fuel mileage with it.

I'm not sure what the long term consequences of doing this are, but your engine isn't designed for high octane gas. It is possible the misfire is being caused by to much octane in the gas. Although, if that were the case, I would have thought you would have seen the problem more immediately (as you say you've been running it for over 2 weeks).

 

[shadowless127]

I'm not sure what the long term consequences of doing this are, but your engine isn't designed for high octane gas. It is possible the misfire is being caused by to much octane in the gas. Although, if that were the case, I would have thought you would have seen the problem more immediately (as you say you've been running it for over 2 weeks).

From what I've read using higher octane gas compensates for the 10% ehtanol that they put in gas now. Besides I figure I'd get a random misfire if it was too much octane, not a misfire on just one cylinder.

 

[sport97]

You could always run seafoam through it. Maybe you have a stuck valve or something like that, that might cause it to misfire. Seafoam can help with cleaning the valves i think.

 

[shadowless127]

it was the spark plug wire. Cars runs great now .