Ok first off let me paint the picture. I have an 03 WRX with 47,700 miles on it. It's modded with an APS Cold Air Intake, APS Catless Up-Pipe, APS 3" TBE, APS BOV, APS 525 FMIC, and a Greddy Profec B SpecII boost controller.

Without any sort of ECU management I am obviously throwing a code for my emissions, but I have also thrown 2 additional codes that I was wondering about. The first issue is exaust temperature. I don't feel overly worried about that but since I don't know that much I figured I would ask how serious an issue it is?

The other code worries me however because it is a Lean Conditions code. Now I have heard about #3 cylindar running a little lean with the stock fuel rails and lines, and I know that the cold air intake is leaning out my car a little as well. If I just upgrade my fuel rails and lines should that be enough to take care of the issue or what am I going to need to do to ensure that I don't go throwing this code again? I already have the rails and lines but was going to wait until I got the injectors and larger turbo to instal them. Any help would be apreciated.

P.S- I know I need to upgrade my engine management, it's priority #1 on my list. Until then I just don't run the car very hard at all.

 

I'd be upgrading the fuel pump first, since I don't see that on your list of mods that you've done, or are planning to do.

What are your boost settings like? If you turn it up too far, that'll lean out your engine considerably. Your emissions code...are you running hi-flow cat, or catless? Exhaust temperature (high) is indicative of a lean condition, so I'd set the boost lower, and help enrich the air/fuel mixture.