[MattB]

Between 4000 and 4800 RPM's I see a lean spot and -1 degree of knock correction. Is this normal?

When I say lean I mean 14.7 is the worst of it...

I have a new O2 sensor that I am putting in tonight because I am getting a misfire code that Supers solved by replacing the 02 sensor. I don't know if that will make any difference with this but I figured I would post and ask.

I have Delta 2000 cams, Borla headers, and a cat-back.

 

[Not-Ewrx]

I'm not to sure how the KC works on the NA subaru ECU but on the turbo's there is a stored table of correction that can do this durring certain rpm ranges. Since it's stored it may have just been some crappy gas. I would try doing a reset and seeing if it's still there.

 

[MattB]

I just reset yesterday and ran Shell 87 octane gas. I will give that a try though. Thanks.

Any other things that could cause this?

 

[Not-Ewrx]

Are you on the stock ECU? Without Wideband O2 readings how do you know you are running lean.

 

[MattB]

The stock front O2 sensor is a wideband on a 2001 (http://www.rockauto.com/catalog/raframecatalog.php?catalog=23&partnum=17018&a=FR23-17018) or so I thought anyways... Yes it is the stock ECU. Getting readings through RomRaider and ECUExplorer.

 

[BLACK 05 RS]

Is this at wot? It is normal to be lean for a very short duration of time just at tip in as the car goes from CL to OL fueling. If you have been at wot from low rpm through this rpm and the AFR rises then it there is something wrong, possibly injectors, or fuel pump. Does the AFR go toward rich as you pass this rpm?

 

[MattB]

Yeah it just gets lean for a few hundred RPM then drops back to normal and the KC goes back to 0 degrees.