Acknowledgements: I got this tip from the SSCOR
mail list.
| What is the Sebring idle droop on a 1.8 miata? This happens after your car has warmed up. When you come to a stop and let the engine idle, after about 20 seconds the idle drops 200-300 rpm and the car starts to shake, unless you had set the idle higher to compensate. If you have a vacuum guage, you can see the vacuum decrease by 4 inches. Blip the throttle and the idle will go settle back at normal for a few seconds. Then it drops again. If you're used to the steady smooth idle of a stock miata, this sucks! |
 |
| This fix worked on my car. Locate the small rubber hose that is on the body of the Eaton supercharger. It connects to the air filter. Put a clamp on this hose. |
|
| The clamp doesn't need to be very fancy. I just took two L-brackets and held them togther with a nut and bolt. For an elegant fix, use an aquarium air valve (brass - plastic will melt). |
|
After clamping the hose, my idle went up 200 rpm. I adjusted it back to 800-900 rpm and it's steady now. No more idle droop. I believe this fix works because this line lets the engine breathe air that's not metered thru the mass air flow sensor, so it's like a vacuum leak, Restricting it makes it a more controlled vacuum leak and the car's idle control system works better. |