[7angofragger]

I cant see AFR in the combustion chanber, but i can look at my plugs. The plugs have less then 50 miles on them, so there good. The plugs are clean as heck.. hardly any fuel is on them. The upstream o2 is just a replacment bosche. its a narrow band. i have basic mods. its the factory comptuer in the car. it has an intake, and it has a 3" 02 housing comming off the turbo, and going straight into the 3" open catless downpipe. when i unplug the upstream 02, the car goes into limp mode, and starts dumping tons of fuel. my afr's go to about 11 at idle. as soon as i plug the upstream back in, the pcm tries to lean the car out. it tries to reach a 14.7. when that happens, it starts to sound like it has a massive cam in it... its starving for fuel. i have a hand held tuner that has tunes for the factory injectors, and a set of 600cc's. the car has ran awesome since i have had it... over a year. after i put on the exhaust on, i drove it for 1300 miles until it started acting up.