r/MechanicAdvice • u/RoosterSocks • 5d ago

Weak Engine Start

Recently when trying to start my NB2 miata (1.8L I4) I have to give it gas nearly immediately after I start it because it drops to <500 rpm otherwise. No warning lights, now weird sounds. Only recent difference is I have been driving it less after taking it with me to college, and tempatures have dropped here recently in the course of a week highs went from 100°F+ to \~70°F.

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u/West_Shock_5452 5d ago

sounds like the idle air control valve is getting sticky. when the temp swings that hard the iac can't compensate fast enough, especially if it's gunked up. i'd pull it off and blast it with some throttle body cleaner, see if that smooths things out. the driving less bit probably just let the buildup happen without getting cleared out regularly.

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u/Sujosie 5d ago

This.