joeybutts

I had my check engine light come on back in the beginning of the summer last year and got it tuned, and the light was gone till about 3 weeks ago. The only thing that was added to my car afterwards was my catback. Is there anyway the catback threw off the A/Fratio so that my ECU would say i had lean banks running on both sides? The car has a few spots where it hesitates, and when i come to a stop the RPM's drop to as low as 3-400. It has never stalled and the idle is a bit rough, wavering between 600-800. Could my MAF have moved and caused an issue? I'm going to call the dyno shop tonight that did it to ask them. Any ideas for me to try before i set up a time to see them?

joeybutts

could my O2 sensors just be bad? Is there an easy way to check them?

joeybutts

anybody help with this?

theorgnlimprtkillr

does your check engine light blink?

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ShadowDrake

Aftermarket tunes lean out the A/F ratio, which yields more power... That combined with another minor problem may have tripped the check engine light.

First thing to check: Check for loose vacuum lines... A vacuum sucking in unmetered air would cause it to lean out fast and you would be experiencing a poor idle and hesitation. While you're checking for loose vacuum lines, disconnect the battery and leave it disconnected while you're searching. After about 15-20 minutes, reconnect it and go drive for a little, the problems should be fixed and the car will not act like it normally would for the first little bit while it re-learns its fuel curves. This can take anywhere from 20+ miles. If the check engine light comes back on in that time you have a more major problem... you may have to clean the MAF (it moving will not cause problems), or it may be something unforseen... someone with more expertise than I will have to step in and reply.

Reed44

My check engine light came on after installing a cat-back and CAI. The code said it was lean. It may sound odd but by adding the cat-back itmay have caused it to go leaner and throw a MIL light. Like shadowdrake said, tunes make it run lean, so by adding the cat-back it might be to lean now.

joeybutts

Ok, that is what i thought. So adding a cat back is a good reason to geta tune done if you already have a tune. Thanks guys! If anyone has any other opinions please let me know!

joeybutts

sorry, the check engine light is steady, not blinking.

Nitti00GT

Mine said that too. I was confussed cause the tune turned off the rear O2s but I got the front O2s replaced and the light went away.

joeybutts

How much to replace them?