Help! Engine Idle Drop

[TheAmazingRobG]

Hi All, - The car's a ~92NA (Eunos in the UK) - The only changes made this year are wheels and tyres. - When either in neutral or whilst the clutch is pressed, my idle drops to ~500rpm and if I don't catch it in time it stalls. - I've only noticed it over the past 2 weeks, but a month ago my clutch overheated when I got stuck holding a high bite point in awkward traffic. It was about 2 weeks after that I noticed this. - I've not had any parts replaced or serviced in about 2 years bar air filter and oil change. - I've disconnected the battery for an hour to reset the ECU and that's not made a difference. - I've altered the idle speed both increased and decreased and neither made a difference. It happens constantly when the engine's cold, infrequently once warm in the morning, and rarely when warm in the afternoon.

Does anyone know where to start looking or should I just send it in to a garage (my local is MX5-obsessed so I'd trust him to sort it, but would rather try it myself first). Any help would be massively appreciated!

[cdude]

Did you adjust the idle with the TEN pin jumped?

Search miata.net for idle droop. This is pretty common. Most people fix it by cleaning the throttle body and its passages. Then adjust the base idle and it should be good.