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Cobb Stage 1+ AFR all over the place

smanierre

Autocross Champion
I just installed a Cobb Big SF intake and put on the corresponding stage 1+ big sf tune. I noticed that while maintaining speed or slightly accelerating, my AFR varies from 13-16. At first I thought maybe my foot was moving on the gas pedal but it does the same thing with cruise control too. Is this a common issue? Also have no codes related to this and occasionally when I give it gas it bogs down and drops to an 11 afr then picks back up as it goes to ~14.7.
 

weidman.matt

New member
It is not an issue at all that sounds completely normal. Your afr is not always consistent as temperature and air pressure and a lot of other factors change and the ecu will make adjustments accordingly. Our cars tend to stick around the 14.7 mark as they are direct injected and therefore run a little leaner by nature than other injection types. When you are going full throttle that is where your ecu is demanding more fuel so the afr goes richer. Im not a complete expert but it sounds like everything is functioning normally.
 
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