Routine spark plug change and getting ready for VT trip. Plugs have 40K miles and look pretty good. All of the gaps were about the same so the electrodes were not very worn. Truck now has 181,000 miles.Truck ran great with the new plugs, until a few blocks later the "Service Engine Soon" light pops on. Code was P0332, Knock Sensor Low Input Bank 2. Cleared the code, drove a little longer and it came back on.The knock sensors on the big block are on the outside, not under the intake like the 5.3 and 6.0, so they aren't subject to failure due to coolant soaking that GM issued a TSB on. Aside from the sensor itself, the other likely cause was a weak spark in one of more cylinders. Since the plugs were all new and properly gapped, I figured I may have damaged one of the wires during the plug change.A quick trip to NAPA for a set of wires, and problem solved. I took a loooong highway route with hard acceleration and high speeds, no codes returned, so am hoping this is solved. Now if I could only find my short 3/8 extension....it popped off the socket after tightening plug #7 and darned if I know where it went....

If you did not run ac delco platnium in it. Other plugs qill cause all types of things

BurbMan wrote: Now if I could only find my short 3/8 extension....it popped off the socket after tightening plug #7 and darned if I know where it went....That's why the check engine light came on. It was your knock sensor picking up the knocking noise of the 3/8 extension hiding on the engine, banging against the framitzz valve!. It was "knocking"!It was telling you where the extension is! You have to decipher the trouble code a little closer! :B :B

Plugs are AC Delco 41-983 double platinum, only kind that's been in the engine since new.

It is easy to damage a plug wire while replacing the plugs. I bet that was your problem. As far as the extension, It is known fact that if you drop anything in your engine compartment it will not fall through and you will never see it again.I bought a car once that had a plastic smell coming from the engine compartment. Never could figure it out until one day I was looking at something in there and spotted a screwdriver with a melted plastic handle wedged between the exhaust manifold and the engine.

Fulltimers wrote:It is easy to damage a plug wire while replacing the plugs. I bet that was your problem. As far as the extension, It is known fact that if you drop anything in your engine compartment it will not fall through and you will never see it again.I bought a car once that had a plastic smell coming from the engine compartment. Never could figure it out until one day I was looking at something in there and spotted a screwdriver with a melted plastic handle wedged between the exhaust manifold and the engine.My brother once found a wrench with initials engraved on it in the skid plate of a truck he bought new.

8.1L Knock and Update | Good Sam Community

BurbMan
Explorer II
Jul 23, 2018
UPDATE: The light is back on and threw P0332 again. Crazy as it sounds, my theory is the same as BobsYourUncle!! I need to jack it up today and find that extension!! Heading out Thursday morning for camping, so the clock is ticking on this one...

BTW garyemunson, these weren't original wires, they were replaced at 140k about 4 years ago.
garyemunson
Explorer II
Jul 23, 2018
Ater 181000 miles, I'd expect the wire to be on their way out. Plug wires are still FAR better than they used to be. I remember back in the 60's, after two years you could open your hood at night and see sparks jumping all over your plug wires as the engine idled.
wnjj
Explorer II
Jul 23, 2018
Fulltimers wrote:
It is easy to damage a plug wire while replacing the plugs. I bet that was your problem. As far as the extension, It is known fact that if you drop anything in your engine compartment it will not fall through and you will never see it again.
I bought a car once that had a plastic smell coming from the engine compartment. Never could figure it out until one day I was looking at something in there and spotted a screwdriver with a melted plastic handle wedged between the exhaust manifold and the engine.

My brother once found a wrench with initials engraved on it in the skid plate of a truck he bought new.
Fulltimers
Explorer
Jul 23, 2018
It is easy to damage a plug wire while replacing the plugs. I bet that was your problem. As far as the extension, It is known fact that if you drop anything in your engine compartment it will not fall through and you will never see it again.
I bought a car once that had a plastic smell coming from the engine compartment. Never could figure it out until one day I was looking at something in there and spotted a screwdriver with a melted plastic handle wedged between the exhaust manifold and the engine.
BurbMan
Explorer II
Jul 22, 2018
Plugs are AC Delco 41-983 double platinum, only kind that's been in the engine since new.
BobsYourUncle
Nomad
Jul 22, 2018
BurbMan wrote:

Now if I could only find my short 3/8 extension....it popped off the socket after tightening plug #7 and darned if I know where it went....

That's why the check engine light came on. It was your knock sensor picking up the knocking noise of the 3/8 extension hiding on the engine, banging against the framitzz valve!. It was "knocking"!
It was telling you where the extension is! You have to decipher the trouble code a little closer!

:B :B
newman_fulltime
Explorer II
Jul 22, 2018
If you did not run ac delco platnium in it. Other plugs qill cause all types of things

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