It is an A'/C problem?
 

Hi Guys!

Syntoms:

Turn on the A/C, running for 15-20 mins. After awhile, the car's power go ON and OFF.

Turn the A/C off , wait for a few minutes, and its fine again.

Never happens with A/C off.

Please advice?

Sounds lke you A/C compressor is cycling. Happens to all Miata (with A/C systems). Shouldn't be too noticible with a FI motor.
If the system is cycling quite often (30 seconds or a minute) then you need to check the charge in the A/C system....

Are you saying that the engine stops? Or that it just lost power?

Lost of LOTS of power! feels more of a surge, when you flood the engine with fuel, its even hard to climb a slope.

Thanks for the responds guys!

OG, the Engine just lost most of the power! and ones I turn the AC off.. its back to normal :confused:

Could it be that the AC Pump just locks up?

What could it be?

Try it with the AC off and see if it goes back to normal. That will isolate the problem if it does. I even run my AC at autocross and don't loose power, so a big power loss is probably the compressor locked up when the clutch pulls in.