I keep getting a check engine light but can figure out why (MAF Circuit high) on a 2003 miata turbo. Doesnt appear to be ECU replated.

I notice that my car will some times go lean but when i try again i cant get it to do it to recreate the problem. This usually happens above 5K rpms no boost.

Also in boost I will have an AFR close to 11.1 but the car will suddenly buck and back fire as if I hit a hard rev limiter. Its random but always happens above 5K rpm.

I'm at a total loss. But any time it happens I immediately get a CEL.

What i have done that solved a large portion of this issues but did not eliminate it completely.
Cleaned the MAF
Cleaned out the intake manifold
Replaced plugs and wires

 

You are getting a high MAF circuit because you have hit 5V on the
MAF output somewhere, sometime. Usually only happens if you are running more than 12 psi though.
Stephanie

 

Thank you Stephanie,

So the Miata does have a MAF limit? I didn't think of it because I have hit 15 psi before in an accidental boost spike with out any problem. But i was running the xede that lowers the MAF signal. I have read that I didn't need a MAF clamp in a Miata but I will give it a try anyway.

Right now I have an occasional rare spike to 12psi, I need to make some adjustments to my boost controller. I might also need to check for boost leaks but dont have the equipment to do it at the moment.