Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Why is my car running lean????

i need some help why is my car running lean? cause i took it to autozone and itsaids my car is lean... and ever since i put thecold air on it, is been runing lean but it still runs strong and all but anyone knows why its doing that help me out thanks....

When you put the CAI on, did you reset the computer? If not, try pulling fuses #4 and #11 for about 20 minutes or so. Replace them, start the car and drive around for a little while. The computer should hopefully relearn its settings and adjust the A/F ratio.

I'd be more willing to think it is a leak in the intake after the MAF or the MAF is positioned in such a way it is not getting a proper reading of the incoming air.

That's true, but since you shouldn't have to touch the MAF or anything after it to install a CAI (or am I wrong?) I was assuming that everything was status quo there. Yes, I know ass, u, me... but the computer reset is always a quick and easy first step.

Something else I thought of: on non SVTs you have to remove the IAT from the airbox. Many people leave it dangle somewhere near the intake, but that may affect how the computer sees the incoming air. The temperature readings may be off because the IAT is not sensing the air that's actually going into the intake. CEG18 doesn't say whether his car is SVT or not...

Originally posted by CEG18:

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i need some help why is my car running lean? cause i took it to autozone and itsaids my car is lean... and ever since i put thecold air on it, is been runing lean but it still runs strong and all but anyone knows why its doing that help me out thanks....

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Hmmm... How did autozone determine your car was running lean? Was it because of a CEL code like these:

P0171 System Too Lean - Bank No. 1.
P0174 System Too Lean - Bank No. 2.

These are classic signs of an O2 sensor failing. You may be running lean, but you might want to find out how/why autozone figured this out before trying to solve the problem. Last I checked, AZ wasn't really up to checking air/fuel mixtures, so I'd be curious on how they came up with the 'running lean' story.

yea they told me those codes but bank one was lean and bank two was rich... but yea they told me thosecodes...if that helps out anyway let me know..

If your CAI was causing a problem, you would be lean in both banks. Since you are only lean in one bank I might suspect a bad O2 sensor. Before replacing anything, I would check to make sure the UIM gasket is OK. Lean in one bank and rich in the other is strange. Have you ever remove the UIM? Might also check the secondary linkage to make sure the different sides are connected and working OK.

So exactly what were the codes they read?

okay well chech this out;i bought a Pro-Flow Remote Optimizer and when i adjust it... autozone it was runnin 1 bank lean and 2 bank rich; okay and when i take it off and [censored] it said both banks are lean??? so i unplugged the optimizer for now... but like i said 1 bank lean and 2 bank rich when its plug inand when its not the both banks are lean.. soiam keeping it unplug.. so what should i do then? if boths banks are lean???