Misfire Cylinder 3 P0300

[Etch]

I know this an older topic, but I was hoping OP found a solution. I too am dealing with the same problem and I am at wit's end.

 

[Schurkey]

Compression
Burnable fuel/air mix
Spark across the plug gap, at the right time
Reasonably free-flowing exhaust

Which one or more of these don't you have on the misfiring cylinder?

 

[Etch]

Compression

Burnable fuel/air mix
Spark across the plug gap, at the right time
Reasonably free-flowing exhaust

Which one or more of these don't you have on the misfiring cylinder?

Thanks for response. I thought it was spark but then I bought a proper spark tester for HEI. and all sparks are reading normally. I had an erratic spark but the first tester was bad.

I believe I found the culprit to my problems after redoing the compression test.

1=180 psi 2=100 3=175 4=89 5=190 6=85 7=190 8=95

8=95 7=190
6=85 5=190
4=89 3=175
2=100 1=180

 

[Schurkey]

Bummer. The whole right bank is low.