My mark 1 eunos roadster/mazda mx5 keeps stalling when im in neutral. Its usually ok as long as im not using any of the other electrics in the car e.g lights. As soon as i turn the lights on the idle revs drop off and the car stalls. I have replaced the battery as i thought this might be the problem but it is still stalling.

Adam Harris, March 2008

The engine speed drops with lights on due to the alternator being harder to turn. However your problem is likely to be one of two faults. 1) The idle control valve is gummed up 2) The coolant temperature sensor is faulty. Also check for any air hose leaks in the inlet manifold area.

John, March 2008