Hi i just recently acquired a 90 miata with a megasquirt v3.0 i believe the car will start and run sometimes for 5 minutes sometimes for 45 minutes the it just dies out wont start then let it sit for a few and it will start back up im confused about this

 

Get a laptop and cable, connect to MS and datalog whats happening.

http://www.efianalytics.com/TunerStudio/
You will need either a usb to serial adapter or a straight though serial cable.
Tunerstudio can probably autodetect what version firmware you have on it and import the tune that way you can datalog and see whats going on.

 

Alright I have tunerstudio already and the usb to serial adapter and the serial cable I was just wondering if anyone had experienced this problem before

 

If you don't show us a log, MSQ, and provide more details, we can't help you help yourself.

 

You might want to include SOME information about your car other than 90 and "megasquirt i believe"

 

its the fault of a poorly tuned MS.