Tapping Sound Problem

I have a 2002 Silverado with a 4.3 V6 engine. Here is my problem:

Whenever the humidity is high, or it has rained, my engine will start making a tapping sound that excels with the rev of the engine. At first I thought my valves would need adjustment, but when it is dry and hot outside (normal texas weather), the noise isn't there. At first it squeaks, then after it starts to warm up, the squeaking goes away and you can't hear the tapping at idle. If you put a little gas to the throttle, it will start tapping, and it heightens with the revving. Keep in mind, it only does this when it rains and the humidity is high.

Anyone know what the hell is wrong with my truck?

sounds like you probably need a new cap, rotor, and wires.

And beef is good.

Welcome aboard!

Mine has done something similar since day one. I'm almost positive it is the belt squeaking when wet b/c after about 5 mins it's gone. I've never heard it tap, but the squeak is normal for mine (also a 4.3). For the tapping, I agree with blender. I suspect the squeak is masking the tap when it starts off.

Had two astro vans with the 4.3 over the years that did the same thing. Some belt dressing might help with the squeal but a new cap and rotor seemed to solve the tapping. Even the smallest crack in the cap will let moisture in.

The humid weather tapping is indicative of bad wires. YOu can find out easily: On a dry dry evening, wait untill dark. Open Hood with truck idling. Unscrew under hood bulb temporarily, spray a mist of water with a pump sprayer on wires and coil. You will see the blue "pops" easily.

It is time to change wires if you see it. Get ACDelco wires, NOT GENERIC.

As far as the belt goes you should get a new Serpentine belt. Use the Goodyear "Gator" belt. It is the quietest and toughest belt I have found. ($26.99 at autozone).

As far as I know you dont have a cap and rotor, so that wont be necessary.

Good luck to you froma fellow Texan :)

The 4.3l v6 has a cap and rotor