Too lean
 

so i was at my local parking garage with a few buddies last week. as we were getting ready to leave, i noticed my check engine light came on. so being my cautious self, i took it to auto zone and got the free check up thing. turns out my car is running too lean in cylinder back 1 and 2. only mods i have on the car is a stillen gen 3 long tube intake, and a muffler delete. car has about 13,000 miles on it. any advice?

another thing is my RPM during idle changed from 500ish to 1000ish so when i come to a complete stop, my car will jolt forward which isnt the most comfortable feeling
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I understand from many posts on this forum that the Gen 3's lean the mixture. That is the reason they increase performance when installed by themselves. That with the muffler delete may lean it beyond what the ecu views as normal. Thus your lean code for both banks. A tune would fix probably the problem.

Just curious what the more experienced experts on the forum will say.

Need a tune.
With those mods,car is running too lean

Did you disconnect the negative terminal during install?
Are your MAFs clean?

yes i disconnected the negative terminal of the battery during the install. not sure about the MAF sensor. not sure how they would get dirty. ill clean them off and see if that helps


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The rule-of-thumb is:
If you change only intake side OR only exhaust side, you don't need a tune.
If you change both intake side AND exhaust side, you need a tune.

MAFs probably aren't the problem but they are very easy to R&R. One of the first things to look at when engine is running rough.

Disconnect the negative terminal again, and when you plug it back, drive a bit not crazy to let the computer relearn

update!! disconnected my battery and a few day later, i guess my ecu became familiar with it and my engine light went off


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Hi piggy backing on this thread. Would I need a tune if I got the stillen g3 intake and Fast intentions HFC non resonated?

It would be a good idea

Intake mods only - no tune needed.
Exhaust mods only - no tune needed.
Intake + exhaust mods - tune needed.

This makes sense to me :tup: