engine troubble codes on a 86 corvette

[chrisfrom nj]

the check engine light came on my uncles 86 corvette its the same corvette thats running rough i cant figure out whats wrong how do i display the troubble codes is it the same as the camaro/firebird

[IROCdan330]

yes.

[chrisfrom nj]

yes.thanks do i run a paper clip to pin 6 and 12 or 5 and 6

[IROCdan330]

5 and 6...the 2 upper right pins.

[chrisfrom nj]

5 and 6...the 2 upper right pins.thanks

[chrisfrom nj]

i got 2 codes 12 and a 34 i changed the mass airflow and it runs alot better i figured out why the car was running rough not enough fuel pressure

[IROCdan330]

12 is normal when you short the pins...nevermind that one.

34 is MAF low airflow or something...you said you changed your MAF so i assume the problem went away?

When did you check your fuel pressure?
When you just flip the key for priming its the same as being at WOT (no vacuum) it should be roughly at 42-44 psi.

If you checked it at idle it will be considerably lower.

[chrisfrom nj]

i checked the fuel pressure today it was 44 without the vacume line hooked up on the regulator i put the vacume line on it the fuel pressure was low it was around 34 at wide open throttle and idle i blocked off the return line from the tank so the fuel pressure can build up the car was running like new it had power and everything