I used to run a little rich on my a/f guage, now it is all the way lean, only goes up a little when I am on the freeway at WOT. It never goes past stoich. Most of the time as far lean as you can go. Could it be the Ebay ecu chip I installed in my ECU? I have a b16a with PR4 chipped ecu and vtec controller

 

sometimes those ebay chips will advance your timing.. You never know what those chips are doing. I'd say ditch the chip and see what happens.

Nick

 

I have the same problem, except it started when I installed my MSD 6A. I think the gauge is just screwwed because I put in 450 injectors and had gas coming out of my exhaust... and the gauge still said I was lean.

 

Yeah get rid of that ebay chip.

 

sometimes u can foul the o2 if you are too rich.

 

That is probably the problem. If I unplug the O2 sensor, will that create problems with the ecu running lean?

 

Test your wiring, then try a new O2 sensor, they run $20 for generic Bosch 1 wire. Sounds like old age or a bad connection got to you current one.

Beware of the eBay mystery chip, if you're trying to mix it with forced induction, then the ignition timing could be a very very scary thing.