What is this ticking noise from my engine?

(2011-03-11 15:20:13)

1. sniperlif3 Says: I have a 1993 gmc sierra that has a chevy 350 engine. the tapping/ticking noise I hear is a constant tick-tick-tick, at first I thought it was my pcv valve but I inspected more and I was able to hear it a lot more when I took my intake off. And I can feel it when I touch the throttle body. I can't hear the noise very much while in the truck.

Another tapping/ticking noise I can hear happens when I'm slowing/coasting from about 20-10 mph that is hearable while driving that happens in drive or neutral. It seems to be much louder than the other noise but then again I can't hear the other one much while inside the truck. Idk where this noise comes from since I can't check it while moving.

I have noticed also that my trucks idle seems to be slightly rough and it sits around 480 rpms which seems low for an automatic.

These could be different reasons but what would cause them?

2. Chloe Says: First of check the oil. And if it not really low then mostlikely the valves may be bad or just loose. Or if use us low grade gas and low rpm driving like slow or grandpaish it could be massive carbon build up. I've seen cars come in with carbon so bad that its knocking like a f@#$ed up motor but sprayed some chemicals down the intake let it set over night the flushed out the next day. But for urs id try high grade gas right after an empty tank and drive it a lil hard open it up to burn out some carbon atleast every two months.