ACCELR8

My O2 sensor readings are as follows:

O2 Sensor (B1S1) = 0.956
O2 Sensor (B2S1) = 0.919

What can cause one side of the engine to run leaner than the other?

Thanks,

Jim

Tin Indian

I think it is just differences between the Rt and Lft foreward O2 sensors. There output is just not matching. Which sensor is weak? Who knows.

Ferrell

Switch sides & see what happens.

SmaknaSS

iTrader: (1)

Like tin indian said and exhaust leaks.

WS6 GreeN

I've read on this board that theres a baffle of some sort in the fuel rail and that if you remove it, it will make your fuel trims, etc more even?

ACCELR8

Thanks for the replies!!!

The interesting thing is about a year ago I measured the O2s and both sides were very close to 0.96. This year I noticed the car running rougher and it was slower than stock at the track. I measured the O2s again and got the above results.

I think I'll take Ferrell's advice and switch sides and see what happens.

If anyone else has an opinion, feel free to speek up.

Thanks again,

Jim

CAT3

iTrader: (9)

A vacuum leak on side of the intake might also. Leak fresh air in and lean the cylinder out. Never heard of the baffles. Mine used to be that way, then put headers on, and no more..they evened out again.

malibu350

I would think that that is not really a "big" difference....to me a problem would be like one reading .800 and the other .959 or something similiar....

SNAXS

Well the same thing happened to me..Couldnt find out what it was. Changed my plugs and it was all fixed...

Team ZR-1

leaking EGR would also cause imbalance,
a weak or dirty injector(s), a 02 getting lazy. Also dirty fuel filter or lower fuel pressure.

Bosch now says replace O2s after 30,000 miles to assure they are quick in cycling.

ACCELR8

Thanks for all the replies. I really appreciate it!
Originally I became concerned when my car started running rough and ran slower than it did when it was stock. I used Atap and collected the O2 data listed above. Since the O2 readings of both banks have always been very close, I figured this would be a logical place to start looking for the problem.

Again, I appreciate everyone's comments and now I at least have a few ideas of where to start looking. If I figure it out I'll post what I find for anyone who's interested.

Thanks,

Jim