98 k1500 5.0 knocking noise

[jbarlo71]

Just changed the spark plugs on my 98 5.0, now it's got a low knocking noise between 800 and 1100 rpm under load. I went from a auto lite platinum to an AC Delco copper core, gapped them at 0.060. Anybody ever had this happen?

[1997SierraSLT]

0.060" seems a bit too much. 0.045" is the norm according to all the literature I've ever seen.

[jbarlo71]

0.060 is what the owners manual said, just going off that. But thanks for the reply. I'm not getting any misfire codes or picking any up on my scan tool, even on live data feed. It's only when it's warmed up also. Still runs super smooth and has no loss in Power.

[barry G]

take it to the floor on the highway, and simply come down slow.

 

I have a 96 5.0, and changed spark plug wires due to ripped bots, for equal length custom, 8.8 mm.

 

something in the controls knows the difference. I finally simply went to the floor with it, 4k rpm.

gas mileage went up, cold starts are a big kaboom and robust.

 

..or maybe try battery unhooked for a few minutes. Anything with a resistance value is a rock in the computers memory.

winding things faster is easy, coming back down (as repairs often do), no computer clock likes that.