scary engine noises Options

[Jaemus]

hey guys

i wondered if someone could help me with a problem im having with the GT4 (gen3 3sgte)

i noticed yesterday afternoon that it was making some uncharacteristic ticking/rattling type noises as i drove home - faint, but loud enough to hear from the cabin, and only under load at low rpms.

just now, i went out and started it up, and at low revs, as i play with the throttle, it is making a noise that sounds like if you were to tap the bottom of an empty tin with a key - it makes this sound just over 1k rpm (so not at idle) and it gets higher pitched and more frequent as engine rpm's increase. its scaring me and i dont want to drive it till i figure out whats going on (for fear of making it worse).

i cant quite identify where the sound is coming from - but it seems to be anywhere around the top of the motor.

any ideas? if you need more info ill do what i can.

PS. i tried to make a sound file with my camera, but the noise which is clearly audible over the background to my ears, gets drowned out completely on the camera. *shrug

[Newbie]

Sorry for this stupid question, but what kind of fuel are you putting in?