westrajoe

First of all, let it be said that I have used the "Search" function of this forum, and while I got close, I didn't quite find the answers I need. Let me explain to see what everyone thinks. Last summer and fall (car has been in storage since Nov., I live in MI) my '05 GT started getting a reoccuring CEL. I say reoccuring because I can clear the code, but on an ensuing drive it comes back. The code claims I'm running lean. My '05 has a BBK CAI with a Brenspeed SCT 2 93 Octane tune. I also have a 62 mm TB. What's confusing is that these mods have been on the car for years now, but the CEL just developed. So, a couple of questions:
1. I've read running lean is bad for the engine. How bad, and how long do I have?
2. It seems I need to check my CAI and connection to TB. I will do this as soon as I back her out of the garage this spring. Do people concur? Any advice?
3. I've read that disconnecting the battery and then restarting and letting the PCM do its thing might help. When I do this in a few weeks and the CEL doesn't return, am I to understand the problem is fixed?
4. Can a new tune help? Can I contact Brenspeed for an updated tune of some sort?

siggyfreud

1. Yes, running lean can be bad for your engine. The best way to determine how lean is based on the spark plugs. Pull a few of them and compare: http://www.spark-plugs.co.uk/pages/t.../diagnosis.htm.

2. I would get a can of starter fluid, and as the engine is running, spray in short bursts around areas where there are gaskets, or vacuum lines. Spray, and then wait long enough to listen. If the engine revs up, you've find a vacuum leak which can cause a lean running condition. It is essentially air making it into the engine that the engine's sensors do not account for.

3. Resetting the battery may cause the computer to relearn, but chances are if it detected a problem once, it will again given that conditions have not changed.

4. Brenspeed would probably be the best person to ask about that.