sounds like behind RPM gauge. Its just started now that I have all the check engine lights off and im back on road. 97 LS 4 wheel drive. It growls until I put blazer in gear and it almost stalls then rpm jumps back up to 7 hundred rpm and so does growl. If it not 1 thing its another LOL

enough info?????

I just do an upper intake gasket set. sealed well around the spider. if this helps????

Maybe fuel lines are vibrating on body?????? But whats that got to do with the drop in rpm?????

 

*Moving to 2nd Gen Tech*

Check to see if your throttle cable is resting against your PCV vacuum line.

 

Pull the PCV valve out of the rocker arm cover, engine at idle, put a piece of paper over the PCV valve, (vacuum will hold it to the valve). See if the noise is gone.

 

BINGO! Thank you Guys!!!!! You guys ROCK and so does this forum!!!!

 

What exactly was the fix?

 

The PVC vacuum line were laying on the throttle cables. I rerouted them.