95 chevy k1500 started knocking

[95chevyk]

I have a 95 k1500 stepside with a 350 all stock as far as I know.
It has a 5 speed manual transmission.


So I bought this truck 2 weeks ago and it started knocking yesterday, it doesn't do it when it's cold it only starts to knock once it gets to operating temp and if I accelerate it will do it until it hits about 2000rpm's
It does it in neutral and in gear and it doesn't matter if the clutch is in or out. It was also running very rough so I replaced the spark plugs and it doesn't run as rough but its still running alittle rough.
Spark plugs were coal black when I took them out.
I also just noticed alot more fuel smell in the exaust but it doesn't have cats so i may have just not noticed it before now.
Any ideas would be greatly appreciated
Thank you.

 

[Ironhead]

Black sooty plugs is indicative of a very rich mixture (too much gas, not enough air). If the black is also oily, that means bad valve guides or rings. If this is a TBI engine, it could be a problem with a sensor, but that would trigger the check engine light.

When you say it knocks, is it a pre-ignition knock (pinging), or a mechanical knock like a bad bearing?

 

[RichLo]

or piston slap. Have you changed the oil in it yet?

Do NOT run it again until you change the oil, check for metal shavings, and cut apart the old oil filter and check for metal particles.