My car is misfiring, need help?

[rccrain]

I've got a 2005 Chevy Cobalt @ 47K miles.

At about 65 miles through a full tank of gas it started shaking at ignition and the service engine light was flashing. I immediately noticed a huge reduction in power. It can barely manage a steep incline ... but eventually (after stopping and adding 4 12oz bottles of gas treatment), I got it home. It's now day 2 - same problem. To clarify, it has not yet shown any improvement.

I also noticed the car is driving at 1k rpm higher than it usually does. It idles at normal rpm level but still shakes.

I normally get 30+ MPG. This tank is only getting 18 MPG.

Can anyone help me out here with potential problems and solutions? Thanks.

[IMADreamer]

This could be any number of a 1000 things. Go to autozone and get the CEL checked. Then come back and tell us what they said it was. Then we can help.

[rccrain]

It was the ignition coil. Not covered by power train warranty. Anyone else experienced this problem?

[Montecarloman]

Its not unheard of for the coil pack or the ignition control module to go bad. We had a few come through at my work. Most I have heard about however are owner induced problems (wrong spark plugs).

[steve333]

Ignition coil is not covered under powertrain? That sucks.
By the by, I would never add 4 cans of gas treatment at once. Go easy on the stuff.

[nramlow2006]

Originally Posted by steve333

Ignition coil is not covered under powertrain? That sucks.
By the by, I would never add 4 cans of gas treatment at once. Go easy on the stuff.

correct that will destroy your 02 sensor