Misfire - Please Help!

aria

New Member
Apr 12, 2005
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Austin, TX
I have a modded 96 Cobra with a dual 77mm BBK Throttle Body and a Vortec Supercharger running 9# of boost.

Complete info on the car here: http://www.ariakristen.com/cobra/

I'm having problems with a misfire (for the 2nd time).

I recently had this problem and first tried the spark plugs because they had never been changed and were nasty anyway. The problem did not go away so I had a mechanic help me. He found a leak in the supercharger's plumbing - problem fixed. That was just a few weeks ago.

Yesturday the problem returned.

Engine is running rough (sounds just like a misfire - I assume it is)
The car has been smoking a lot on start-up (for the past couple months)
I go through a quart of synthetic Mobile 1 10W-30 every 200 miles or so
Oil is dark only 1000 miles after oil change

I checked the air plumbing for the supercharger and found no leaks or cracks. I tightened the heck out of everthing anyway. I've had the suggestion that it could be an O2 sensor, but I wanted more info before purchasing new ones so that I don't waste my money.

The car as 65K miles on it and the engine has never been taken apart. No forged pistons or any fun stuff like that.