Ok so i have spark, fuel, injector pulse and compression. I have changed the optispark,
tried 3 injector rails, several spark plugs and wires. it only seems to misfire on 8, comes
out wet with fuel and black. intermittently smooths out especially under throttle
any help greatly appreciated

 

If everything checks out OK as you mentioned, then take a look at injector #8, it may be stuck open or leaking.

 

i changed injector rails 3 times. is there a way it is getting the wrong signal, bc i doubt 3 #8 injectors could have been bad.
thank you

 

Check your 02 Sensors my LS1 did the same thing except it was on two cylinders. I have longtube headers and the 02 sensors got water on them which fouled them out during a rain storm. I changed them and it fixed it. I know yu have a LT1 but they work basically the same in that regard. Maybe this will help you.

 

Why are you changing injector rails instead of the injector? Are you sure the plugs are fouled with fuel and not coolant?

 

I got a lean right o2 sensor code 62 for the first time the other day. i pulled it and it was black like my #8 plug had been. i changed the sensor it but still get the misfire.

im sure its not coolant and you can smell raw fuel when it is missing more. it misses really bad at about 15% throttle when im cruising. if i let off or accelerate it clears up a little bit. my mechanic friend helping me said to change rails because we had two known working engines with full working rails.

i think we are going to try to change the tps and throttle from another engine. maybe try another set of wires just in case. i used bosch platinum plugs, i think they are still fine, my mechanic says they dont foul easily