I'm using autotap to log my 97 Z28, and today the car has started to run rough and stumble. It is reporting a misfire on cyl's 4 & 8. I'm suspecting it is from a bad plug wire, but I haven't had time to check. My question is that now my Ltrim for bank 2 is reading 25% constantly, and bank 2 sensor 1 is cycling between 5 and maybe 300. Would this lean condition be from the misfire?

Thanks

 

Correct, if a cylinder doesnt fire it will push all that unburnt oxygen down to the O2 sensor and look lean on your autotap.