Ok, so I've had my WSP Y, B, Cat, and exhaust on for quite some time. There was a problem during install which required a slight modification to the pipes in order to bring the pipes back up into the car. That being said, this is the strangest thing...

Certain Minimum Conditions:
6th gear @ 2400 RPMs for 2 minutes at steady speeds

Everything else has varied:
Weather, Location, Uphill/Downhill, Elevation, Engine Running Time, etc.

Problem:
Whenever I'm in 6th at 2200-2400 RPMs for more than 2 minutes at a steady speed, I get an error P0109 and P1147. Both indicate the O2 sensor is bad. But when I reset the code with a code reader, the light doesn't come back on until I meet the conditions again. If I try it at 2200-2400 RPMs in any other gear, nothing happens.

The service manual states that the O2 sensor didn't detect a switch from "rich to lean" and back enough times within a certain period, and throws the SES light on.

Anyone got any words of wisdom on where to look? I've tried getting Dallas on the phone for quite some time, but he's never in the office.

Note: I've got the following engine mods: WSP Y, WSP B, WSP Cat, Excelerator exhaust (temporary fix), Definitive UDP, PR CAI, the MAF ECU update, and a Greddy E-Manage (for air/fuel mixture fixes).

 

I have the same problem . I have an SES light on my Max . The B ipie also does not fit properly on to my Custommaxima stright pipe, it just slides in and the clamps dont hold it in place. Now I get a thumping on the freeway. I have to go get it welded. They should also address the proximity of the o2 sensor to the oil pan, which I mentioned before.

 

My fit perfectly. I just had my WSP y,b, and cat installed a week ago. SES never came on.

 

studman, Sent you a PM regarding info on the WARPSPEED Y-Pipe.