MX5Ireland

hi all, im a newbie!!
I have a 1.6 93 jap import and have been having a little trouble with her recently...
Basically when she is at idle, and also moving down the gears to stop, she drops her revs very quickly and often cuts out if not caught in time. when warming up she tends to idle between 250 and 850 but again will drop and cut out at times. it seems when driving to help if you get to pre empt stopping and let the clutch out very slowly but any unexpected stops mean she drops and you almost lose her. its fine when driving its just in low gears and when stopping. any suggestions/advice greatly appreciated, thanks

Hmm, my first thoughts would be that a sensor may be acting up, causing incorrect fuel mix or air flow. Anyone else??

Hi Molly,
Welcome to the forum!

Give this a go, could be a quick fix :
Dashpot fix

Then I'd check for leaks/hissing around the intake manifold with the car idling, you might be missing a rubber bung/nipple on it somewhere or just have a split in the intake hose like this guy

Steve

get some wd40 and spray around and pipes, gaskets, throttle body. If revs rise , you got a vacuum leak.

You need to adjust your idle speed.I'd say your throttle body is gunged up with shit and needs cleaning with carb cleaner and then your idle speed needs adjusting via by bridging GND and TND terminals in your diagnostic box with a paperclip and adjusting the idle screw on your throttle body until basic idle speed is achieved, should be between 850-1000 RPM.
I think there is a write up on miata.net.I used this technique when I had idle speed problems and it solved the problem and not a problem since.You wouldn't believe the dirt in the throttle body just watch you dont damage the protective coating on it.