95 Geo Prizm Rattling/Knocking

Just changed the spark plugs and wires, distributor cap and rotor then adjusted the ignition timing. After driving about 30mi a loud noise developed at low rpm that goes away almost instantly around 2500rpm. A similar problem on a Honda S2000 can be seen here: http://www.honda-tech.com/showthread.php?t=2546671 but unlike this guy my oil is fine (and obviously VTEC isn't the issue here). Mine's got ~170k on it. Always changed the oil regularly. I've only owned it since ~90k but I don't think any kind of maintenance has ever been done on the valves - should I check clearances, what that tell me about the noise? I've heard that top end noises get WORSE with rpm's though, not disappear. Any help is appreciated, thanks.

Just changed the spark plugs and wires, distributor cap and rotor then adjusted the ignition timing. After driving about 30mi a loud noise developed at low rpm that goes away almost instantly around 2500rpm. A similar problem on a Honda S2000 can be seen here: http://www.honda-tech.com/showthread.php?t=2546671 but unlike this guy my oil is fine (and obviously VTEC isn't the issue here). Mine's got ~170k on it. Always changed the oil regularly. I've only owned it since ~90k but I don't think any kind of maintenance has ever been done on the valves - should I check clearances, what that tell me about the noise? I've heard that top end noises get WORSE with rpm's though, not disappear. Any help is appreciated, thanks.

Is it more of a ticking and does it get faster as rpms go up? if so valves.
The problem could have nothing to do with the tune up. It could have happend at the same time w/o the tune up. A quick fix would be adding 8oz of marval mystery oil to the crankcase and the rest to you gas and see if the noise goes away..

I figured it out. It was the timing belt tensioner. It had spun it's bearing and the roller was clinking around behind the covers.

Mine does the same thing. Super annoying trying to locate this noise.
This sounds exactly like what mine is doing though...parts store says $50 part, now I need to find a lift. Dammit, always something.

I just had this problem repaired! Rattled and stuff till you revved it and then it went away, drove fine...
Replaced my timing belt and tensioner, no change.

They replaced my flywheel, torque converter, main seal and transmission pump. Problem solved for under $800(yay tax refund!).
My flywheel was literally in pieces and the torque converter was also ruined. The pump had spun a bearing. The mechanic said it was a miracle that my car even moved much less drove 10 miles at 55 on the highway to the shop.
The center of the flywheel had separated from the outer rim. Clanky and rattley...
Hope that helps.