86 vette with a code 12 and 34
 

I have seen some of the threads here and some indicate it to be a Map sensor or a Maf sensor. Can anyone tell me what it is and the cost. It seems the Maf is expensive and the Map significantly cheaper.

Car is cutting out after it heats up. Took the codes and got a 12 (nothing) and a 34.

A code 34 is a MAF sensor signal voltage low.
Code 34 indicates:
ECM has seen low air flow (low voltage) for one second when:
Engine is first started
OR
RPM is above 600
TPS above 6%, the engine has to be running at about 2000 RPM in neutral.

You really need to get a Helms Manual to follow the troubleshooting charts to repair this otherwise it's just throwing parts at it.

Code 12 is not a trouble code. It flashed 3 times at the begining and end of the code reading process. It's there to tell you when the test starts and ends. The code(s) you see in between are your troble codes. Code 34 was in between the code 12 flashes, so that is your trouble code.

Code 34 is indeed the MAF sensor circuit. It's the black plastic thing between your throttle body and air filter attached to the accordian air duct. It has a connector on the bottom of it.

Unplug the MAF and start the car.

If the problem goes away with it unplugged, and returns when you plug it back on, it's the MAF sensor that's bad, and it's expensive. Do that first then come back and tell us what you found.

If got the problem with it unplugged, there are other things that need cheking (see link below), but do that test first and them come back.

Here. Member Agent 86 did this for you.

http://members.shaw.ca/corvette86/Code%2034.pdf

Follow the pdf from Agent86 or the pm sent, for you answer.

All other suggestions are correct.

Car does the same thing when unplugged ......cars still stalls when hot

Also checked injectors and got a reading of 17.2..they seem fine

First fix code 34 before you start getting into the fuel system. See link above.

BTW, ohming the injectors won't tell you anything about leaks or bad spray patterns.