this one didn't get much attention in the LT1 tech forum, so maybe it will here

I was commuting tonight and suddenly the car starts to miss heavily at low rpm, then the engine light came on.
I pulled over and took the scanner out of the trunk; I got a code saying that one of the sensors reported a lean value, so I assumed that the extension got disconnected / burnt by the headers, but it got weirder:

one of the bank has a 108 blm, the other one has a 160 blm! they're both maxed out in opposite directions!
then one sensor reports a steady 2mv while the other goes around 100mv!
to rule fuel / ignition issues, I did a high rpm pull (so that it doesn't use the o2 sensors for feedback) and the car ran great, so I am assuming the problem is electrical, but I can't find what would affect both sensors at once...
I tried to reset the computer to rule out any weirdness there, but nothing different.

any idea?

 

You had a miss right? Was it like an opti problem?
You O2's become basically useless in a missfire situation.
A cylinder that missfires does not use up it oxygen.
The O2 picks up this as extreme leaness.
The PCM adds fuel to an already over rich condition.
That's why OBD-II has miss-fire monitiors & OBD-I only to an extent if any.

 

that's a good point, I didn't think of that; it would explain both banks failing at the same time...

however, at higher rpm it works normal, maybe the miss becomes less apparent there...
I'll do some more testing to see what happens

 

This should be posted in LT1 Tech, if it isn't already.

Thanks.