Intermittent tapping unrelated to RPM

[98Camaro3.8]

This one is really bugging me. I'm getting this tapping that is unrelated to engine RPM or speed. It'll happen while cruising, clutch in or out, or while idling. It's a little loud...sounds kind of like a bad lifter, but it's at a constant rate of about 5 times per sec.

Hard to pinpoint where it's coming from because it'll stop after 10 seconds of idling, then I have to drive it to make it start again. Either from the driver's side of the engine or under the driver's dash.

The fact that it's at a constant rate tells me it's not something mechanical in the engine, but I just can't figure out where it's coming from. Was thinking maybe it was some kind of vibration, but it's the same every time.

Any ideas?

[camaro_speedemon]

Sounds like it might be a loose exhaust hanger.

My only camaro rattled like that. It took me months until I saw the exhaust was really close to the crossbrace under the car. I raise the exhaust piping and retightened the bolt. Then again, I had an aftermarket cat that didn't have both bolts to mount to the hanger.

[shenanigans]

pull your belt maybe?

both my 3.4 and 3.8L both had a tick from a pulley for some reason I just WD40 behind them and it stopped.

[Fbody3400]

Eric, where ya been?

Anywho, in my weekly forum trolling, they're talking about you again. http://www.my350z.com/forum/showthre...1&page=1&pp=20 Its at a 350z page this time though.

[vanbibber]

/\ hahaha [img]graemlins/rofl.gif[/img] that was good reading.

Eric PWND them

[Fbody3400]

haha, that guy with the '95 gts mustang got 3wned badly.

[98Camaro3.8]

Thinking it may have something to do with the injectors. When I get off the gas and coast down, the noise stops. As soon as I touch the gas, it starts back up. Seems to coincide with what the wideband shows regarding DFCO.

Just what the noise could be is still a mystery. If it were an injector making the noise, I'd expect it to change with RPM, yet it doesn't.

[Rowdy Burns]

would you say the noise is excessive when the engine is under load? could possibly be a blown header gasket, which can sound very mechanical but is also directly related to engine RPM.

could also just be the everpresent injector pulse.

[98Camaro3.8]

Definitely not an exhaust leak of any kind.

I would lean toward just an injector tick, except that even that would change with RPM.