Which cylinder is #8 on the 6.0 liter V-8 Chevy Silverado ?

Question edited for clarity. Full year make model in title and mis-spelling of 'misfire'.
Question moved to sub category.

The misfire code only tell you that, unfortunately it doesn't tell you why. When swapping parts to test theories, only swap one thing, one cylinder to one cylinder and only one item, the coil, the plug or the wires, not all three. What was the make of the Crankshaft Sensor? Only buy quality OEM replacements as there is a history of bad ones from Mexico and China.

Wouldn't hurt to check the wires again. This has a neat diagram.

https://www.silveradosierra.com/threads/5-3-firing-order-cylinder-diagram.734633/

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misfires are from coils and injectors
most likely injectors as they are subject to electronic failures and dirty fuel

that would be bad coil packs ,try switching coil pack cylinder 3 with 4or 5 and see if miss fire code changes if it does it's the coil pack .or its possible where they plug in at the bottom(there should be a small oval rubber gasket on coil pack to keep out corrosion or possible not making a good connection (loose) ,oil getting in there ,you can use a timing light to narrow it down faster, pull your plugs for those cylinder and inspect for damage or fouling.and lastly check your wires if any brakes or crakes and that they fit on plugs tightly.

check high tention coil wire, coil wire going to dist cap with test light, if test light light up, it good also check dist rotor, and if that good might be pick up coil , the module might be bad, let me know what happen Bob

what code is check engine lite giving

The sensor for the crankshaft position may be loose or misaligned. You may have a rust spot on the crankshaft interferring with the ability to pick up the #5 position.

Check out your alternator as stray electrical voltage will interfere with the pulses needed to fire individual plugs. Try WD40 on the wires to the coils(plugs) as stray voltage may jump to another plug.

You fixed what you identified, but how about injector pulses? Could easily misfire and give same effect as sparkmiss. You may need to get loaner tools from Autozone or others to test injectors with the lightbulb you insert in the injector harness.

I hope my solution is helpful.

you may have a bad coils or coil boots in those cylinders, try switching the coils to a good cylinder and see if the codes change to the other cylinders, if they change then replace the coils, the computer see it drawing more cuurent so it thinks its the plug because its not misfiring or completly grounding out.

Try swapping the injector on that cylinder with the one next to it and see if the misfire changes to the other cylinder.If it does then you have a plugged or bad injector.It it still stays on that same cylinder then check compression on the number 6 cylinder.Let me know what you find out.Good luck.

1989 Chevrolet K 1500 P/U 4WD
5.7 liter V-8 VIN "K"

Firing order is 1-8-4-3-6-5-4-2
Distributor rotates clock wise and #1 is at the 5 O'clock position "post by the # 7 cylinder.

Cylinder # passenger side front to back 2-4-6-8
Cylinder # dirver side front to back 1-3-5-7

hello tgbarnett99: Number 8 cylinder will be on the passenger side of the motor.4 th. plug back from the front of the engine. Should you need any more help please just ask.Thank You for using FixYa. Roger