more belt woes, and my car doesnt need air, there must be a leak in air intake Options

[opera guy]

I got belt from my FLAPS, finally figured out how to move the alternator to tighten the belt. however, the blet still flaps a lot and eventually will fall off. the belt appears to be chewed up, i dunno why. i dont see a way of checking if the fan and alternator pulleys are aligned correctly w/o pulling the motor.

also, with or without the belt on, my car idles really weirdly. it revs and revs from flat line (almost stalling) to about 1300 rpm. just this constant up, down, up, down...etc between flatline and 1300. there is a distinct continus HISS (is this normal for 914's?) if i cover the inlet for the airbox.. the car idles at about 1100rmp, HISS still present, but no "up-down-up-down..." revving. what am i misssing here.

btw, no mods to air intake, stock airbox with regular airfilter element.

[ArtechnikA]

there is a distinct continus HISS (is this normal for 914's?)

it is NOT normal. you have a vacuum leak, and it is very likely primarily responsible for your wonky idle issues. you'll need to remind us what kind of engine and FI you have, and someone versed with /4 operation can guide you from there.

meanwhile - what you can do - find that vacuum leak ! sometimes it helps to use a 2-3' section of 3/8" (or so ...) plastic hose. stick one end in your ear, move the other end around in the engine room like a stethoscope and zero in on the source of the sound ...

[opera guy]

Its a 1973 2.0. dunno if its L jet or D jet. i'll hve to look up how to tell the difference between the two. thanks for the tip regarding the garden hose. was gonna try blowing cigarette smoke in there but this is probably a healthier idea.

[Toast]

It's a D-Jet System.

If the air box is not seated on the throttle body, you will hear a "hiss".

By putting your hand over the intake to the air cleaner assembly, you are cutting the amount of air going into the engine.

So, either you have a hose that is loose, a line that is not connected, a cracked plenum, leaking cylinder runner rubbers or any number of things in the intake system.

If the alt belt doesn't fit correctly and flaps around a lot, it is the wrong size belt. Get the number they sold you and ask for one that is, say about 1/2" shorter.