I`ve never seen anyone who has had this problem yet.But the problem I`m having is that there`s a humming noise that`s coming from the dash cluster,it`s mainly coming from the left side of the cluster.It hums when I stop,but while in neutral I give it the gas it goes away.It almost sounds like it`s coming from the RPM gauge.I put it in drive, take off it goes away.I know that the gauges are all electric,with no cables to and from the speedometer.Like I said before, I think it has something to do with the rpm gauge.Has anyone else ran into the problem or know anyone who has?

Thanks! Matthew

 

I have seen this many times in the past and went through it myself. The most common cause is the throttle and/or cruise cables resting on the PCV vacuum hose that runs from the intake plenum to the driver side valve cover where the PCV valve is located. The noise is the PCV valve oscillating as crankcase pressure fluctuates with piston travel. Stock check valve style PCV valves are NOISY! When the cables rest on the vacuum line, all of that noise is transmitted to the firewall where the throttle cable is hard mounted. The firewall acts like a sounding board, amplifying the noise. It's pretty simple to reposition either the cables or the vacuum line.

The fact that yours is noisy when in neutral/park and goes away when you move the truck could possibly indicate that your motor mounts are on the way out and engine movement when accelerating moves the two pieces away from each other. Just something else to check out to make sure you aren't surprised sometime down the road.

 

You know what, that`s what I thought it was.I noticed the pcv valve was making a humming sound on the drivers side.My first time hearing a pcv valve humming like this one does.I had an 81 malibu with the 350 5.7 liter V8, the pcv valve never hummed at all.I just don`t get it.Yes, the motor mounts are shot no doubt.It seems as though every time I turn around there`s a new sound or problem.Can`t really complain since my ride is pushing 15 yrs. old with mostly oem parts from G.M.on her.I`m gonna buy the pcv valve that has a 90 degree on it.Hopefully that will take care of the sound transmitting through out the fire wall.Thanks for your time Swartlkk!

 

You know what swartlkk...You where right, you hit it right on that nose.The throttle cable was resting on top of the pcv valve.I mentioned I would replace the straight pcv valve with a 90 degree one.But I couldn`t since the pcv valve has a piece aluminum 3/8 tubing running from the pcv valve to the valve cover.So I just zip tied the throttle cable up to the brake booster rubber vacuum line.WAMMMM no noise.

Thanks again Swartlkk!