The ol' NB from time to time drops 100 rpm or so, doesn't run bad but not as smooth as normal.
I'll have to check for vacuum leaks, that's my first thought, but anything else I should start checking?
The ol' NB from time to time drops 100 rpm or so, doesn't run bad but not as smooth as normal.
I'll have to check for vacuum leaks, that's my first thought, but anything else I should start checking?
Check that the IAC isn't gummed up. The NB has a lot of authority over the idle speed so it's not as sensitive to the position of the idle bypass screw, but you can usually work around the problem by backing that out a half turn or so.
Ok, so car was really dropping idle tonight, throttle inputs no problem, car would rev (which I did to keep car running).
FPR (and where is it on a 2000? If I read right, in tank?), or idle pulse more likely? Quick and dirty test for either?
I'll probably just take it in, it's my daily and no more spare cars after selling the focus and e30, and I suck at diagnosing.
Mine does this on occasion as well.
Honestly i think the iac needs cleaned first.
Let us know what you find
If the iac is at the bottom of the intake at/ near the opening, it should be plenty clean, done when I had the random dying w/o codes issue before (which turned out to be the fuel pump).
Cleaned both the unit itself and the air passages with copious amounts of tb cleaner.
Ok, cleaned the IAC, not much to clean. Car seemed to avoid the problem for a bit , but it's back to dipping 50 to 100 rpm (we'll see if it gets worse like what generated my last post here....).
Seems to do it more in cooler weather.
Anybody else ever have this problem, all the Miata owners on here? Or am I just luckier than most? 
Is it when cold or hot or both? Mine has issues for about 30 seconds but only after it's sat for 10-30 minutes.
In reply to Stampie :
same with mine.doesnt idle well after it has been off for about 10 mins and is then restarted
It's all the time. I.e. as soon as the "choke" is off after a cold start the idle will just decide to drop revs.
The other night it was dipping to 500 or 600 rpm (at which point I added throttle to keep it going).
Usually it'll just drop 50-100 rpm, not feel happy idling for about 3-5 seconds, and then pop right back to 850-900rpm.
Does it about once a trip, length of trip doesn't seem to matter.
Mine seems to drop to a very low RPM idle on very hot days sitting in traffic. Other than that, no. (mine is a 95, well a 96 motor back-converted to OBD1)
If I blip the throttle juuusst right it will settle into a normal idle.
But, thats a middle of summer DC stop and go traffic issue.
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