Hey all I have a new 1991 firebird. The VIN says it's a 305 but the previous owner said it was swapped out to a 350 but she didn't seem like she knew what she was talking about so I'm not sure. When I got the car I reset all the saved codes and dealt with the ones that popped back up immediately. I did see the code 43 in the history but I drove about 300 miles without it coming back. Last week I stopped at a gas station and the only fuel they had was 93 so I filled up with it. Now however, the code 43 is coming back once the car is warm and I accelerate hard causing it too run badly. I read somewhere that this could be because of the fuel not allowing it to pass the knock test? Thanks for the help.

 

Hmm I've never heard of that?? Have you checked to see where your timing is at? And is there a performance chip installed?

 

Yes, the forced knock test is failing due to no knock.

RBob.

 

Awesome thanks RBob. I guess I'll just run this tank down as fast as possible and go back to 87.