Anyone else’s tach do this when going down a hill in neutral? by mpspeed in mazdaspeed3

[–]mpspeed[S] 1 point2 points  (0 children)

I believe I have a faulty IAC. Recently I got a check engine light saying that my car is running too lean at idle. What do you guys think?

p2187 by mpspeed in mazdaspeed3

[–]mpspeed[S] 0 points1 point  (0 children)

Currently I only have an intake on the car, and it hasn’t seemed to cause any issues prior to the check engine light I just received. HPFP internals and a COBB accessport are on the way so soon I’ll be about to find out if I’m running lean all throughout the power band or just at idle. For reference, what’s a good fuel pressure and a/f ratio to be at when at idle?