Hi, Does anyone have any help on codes 3 & 15. I know what the codes are from the service manual and have done everything except replave the ecu. I have replaced the o2 sensor and the cas. I have a bipes and a olderguy's o2 clamp installed on the car. It is a 93 with a 1.6 and intercooled greddy setup. I didn't want to replace the ecu so any help is appreciated. Thanks

 

couple guys are experts on miata.net, i had my trouble with codes as well so i posted and was responded few minutes after my post

 

I suppose because you say you've replaced the o2sensor and the CAS that a code 3/15 covers those 2 items? OBD1 usually just tells you what part is faulty, but nothing specific. Grabbing a spare ECU and swapping it in would cover a lot of ground for you. You don't have to buy a new one.