My car won't idle and I checked for codes anf it gave me the 12 three times then flash flash puase plash three times does any one know what this means or how I can find out.
thanx

 

World,

You didn't miss anything. The DTC "12" is normal. You should always get that code, since it means that the ignition is ON but there are no distributor reference pulses. (Well DUH, GM! The engine isn't running! I always wondered a little why that code even existed, but there are a few cases where it can be useful.)

If you got no other error codes, that is the first step of the process out of the way, and means that nothing is significantly wrong with a sensor or the ECM.

What year/model/engine do you have? The common problems for poor idle will vary depending on the engine and fuel system. And a thorough description of the problem would help, like just a low RPM, or shaking, any noises, etc.

Waiting for info...

 

It's a 87 GTA with a 350 95k miles
I can get it to idle after it gets hot if I just keep pressing the gas when its about to stall. When it is hot it hesitates when you first step on the gas. When it is hot it takes about 5 seconds to start. I got a ajustable fuel pressure regulator because the old one didn't hold any vacume and the car seemed to run best at about 36 psi seems kinda low but I live at 4500ft and there is less air. An exhaust probe said the air/fuel mixture was all over the place. The o2 sensor looks like it has been replaced even though I heard they will die if your car is running bad. I guess now I will try looking at the fuel filter and IAC maybe a new tps connector. I'm going to check the maf like you posted for randomly won't idle. Is thier anything else it could be.
thanx