[ADHelms]

4.7L 285 V8
After engine start, there is what sounds much like a loud 'ventilation fan' instead of the normal idol tone. This noise has recently started after a change in spark plugs and the breather tubes from the back of the engine back to the resonator. I have noticed performance reduction from initial take-off power and MPG. Can someone help me narrow down the noise? I have a hard time explaining the sound but I hope we can narrow something down.

 

[RogerRamJet]

Howdy, ADHelms, and welcome to the forum.

Taking a shot in the dark here with an educated guess. I have the same truck as you, white of course, and the only thing I can think of is that perhaps you didn't put in OEM plugs and the engine is using more gas to get the same spark. And with more gas comes more air. So what you're actually hearing is the intake sucking in more air to compensate for more gas, which would explain the reduction in performance. If the plugs are not OEM, put some OEM plugs in and see if that fixes it. Let us know how it turns out or if we can help you further. There's bound to be a few others chime in with their two cents.

 

[ADHelms]

Reply

I think I will try the OEM plugs to see what happens with the gas; however, I'm not sure that engine noise I'm hearing is the cause by the plugs, but then again it could be. I will give it a shot and let you know what happens.

 

[RogerRamJet]

Reply to your reply

I think I will try the OEM plugs to see what happens with the gas; however, I'm not sure that engine noise I'm hearing is the cause by the plugs, but then again it could be. I will give it a shot and let you know what happens.

Excellent! If that doesn't fix it, we can look at a few other things.