I have a 02 Miata and whenever I start the car it will idle and everything fine in neutral as long as the clutch peddle is pressed down but when I release it the engine dies. It doesn’t stall or lurch like it’s stuck in gear the rpms just slowly drop and die even if I try to rev it. It was throwing a CAS with an 02 sensor code but I replaced the CAS and it would idle without the clutch but only for a minute then it dies and won’t idle unless the clutch is being pressed down once I start it again.

 

Im having a similar issue with my 01. I replaced MAF, IAC, O2, Fuel pump, spark plugs, coil packs and wires, and at this point I dont know what else to replace in order to get the car running right again.