92 MX3 KLDE Runs Rough
 

I have a 92 mazda mx3 with a klde from a 626 and it was running perfect up until about a week ago when it just up and died on me, i plugged my scanner into it and hit read codes as soon as i did that it ran perfect, so i jumped the TEN pin to ground on the diagnostic port and the car runs fine, Any ideas???? I was thinking about getting a ECU to try first otherwise bad ground somewhere??

Were there any codes at all? Interesting the car runs fine with code reader hooked up and same with TEN and Ground jumped. I'd wonder about the ecu too.
When hooking up a code reader or jumping TEN and ground (basically the same thing, from what I've read), does it change the mode of the ECU when engine is started? I don't know... If it does, whatever changes, sensors operating, operating parameters, etc., may be a clue as to what is happening. That'd require more research...

Cleaning ground points is never a bad idea, especially if something electrical is at fault. Plus, it's a cheap fix that can only help your car.