Well my check engine light was on so I ran the ECU and got error code 0304(knock sensor) and 0302 (EGR System Hi/Low Flow), knock sensor i know but what the hell is "EGR System Hi/Low Flow"?

 

Reset and see if it comes back. I triggered mine the last time I pulled out the fuel pump fuse to change the fuel filter. Never seen it back since then.

 

I reset it, now I got no check engine light at all. When I got the car the check engine light was on but the mechanic said it was the heat sensor and replaced it. He also said the knock sensor was fine, just the harness was dirty so he cleaned it. My wife put 89 octane gas in by accident could have set off the check engine light? I'd rather not replace the KS if I don't have to.

 

89 octane COULD set it off, but if the knock sensor is working properly, it will just retard timing when/if the 89 octane gas causes pre-mature detonation and therefore be working properly (not trigger the light).

 

Well the light is back on again, i'm just gonna replace the KS and see what happens.