I recently got my car dynoed and my air fuel ratio was really lean, some guys on here said well their equipment must be off and what not because you can be running that lean, but I know for a fact my car has ran lean in the past because it set off my O2 sensors and my cel came on. I ran the code and it said that I was running lean. The guy at the dyno said that he thinks I have a different tune on the car, which the previous owner would of had to have done. My Question is if my car has been tuned for running premium andI'm running 87 octane could that make my car run lean? If not what are some ways to fix this problem?

 

If its tuned for 93 octane id run 93 octane cuz one day you might get pinging or knocking.

 

I dont know if it is tuned or not, like I said the previous owner could have done it but I bought it from a dealership so I have no way of knowing. The only reason I think it may have a different tune is because its running so lean.

 

ahhh i see...

 

well what was your air/fuel if it was running so lean? can u post the graph or at least give a break down?

AND why not run premium in the mean time until u find out

 

It was 18 until 4600 rpms, then it started to go down and leveled off at 13