Please help everyone,...94 z here that just developed a BAD miss throughtout the entire RPM range!!! opti/plugs/wires changed 3 weeks ago... it will have this bad miss but as soon as the check engine light comes on...the car runs not perfect but pretty good. Anyone have any ideas?? also, i had the car scanned the other day and it said that the LEFT BANK 1 was running lean...?? But for some reason the car is dumping a crap load more fuel on that side compared the the right side... anyone have any clue?? please help,thanks
Randy

 

It could be an O2 sensor going out.
Your ecm could be reading the faulty O2 and screwing up the a/f ratio, then when it realizes it's crap it adjusts for what it thinks is optimal, whether that's just a calculated guess from the ecm or based on the other side I don't know. But it sounds like a sensor to me, and if one side is acting different from the other, it has to be localized to that side. At least that's my best guess.

 

I changed the left side 02 sensor last night thinking that based on what the scan said that this would fix the problem....unfortunately it didnt...i wonder if i changed the other side if that would fix the problem???...not sure, any more suggestions?? should i change the right side too??? let me know guys, thanks
Randy

 

You should try driving the car around for a while with both of them out and see if it runs better. It's what I would do before buying parts and not being sure.

 

drive around with both of them out?? really?? that wont hurt anything necessarily would it?? also, i changed the other (passenger side) 02 sensor this morning and it didnt do crap!!! Any more help out there is greatly appreciated, thanks
Randy

 

A misfire can cause a O2 to read lean, since an O2 reads oxygen, not fuel, and the unburned air/fuel mix going into the exaust can increase the oxy. content of the exhaust, the PCM then adds fuel to compensate


check your plug wires(burned, ect.,), check for vacumn leaks

 

thanks for the reply dave...i checked the plug wires and from what i can tell they look fine, checked all the rubber hoses going into the intake and i cant see any problems with them that would cause a vacuum leak unless i'm totally blind(which is the case some times...). I need someone else who has not looked at my car to look at it in case i'm missing something (which i obviously am), if anyone can look at it and help me figure it out i would be very grateful. Please help if you can, thanks
Randy