bizarre engine noise

[treed2@u.washington.edu (treed2@u.washington.edu)]

Driving my 16v around the block today, I noticed that the lifters were
making more noise than usual so I decided to go for a ~2 mile drive to try
and build up more oil pressure and see if they quieted down.

They didn't .. I checked my oil level and it's full; the oil is about 2200
miles old. I'm gonna put some marvel mystery oil in there and see if they
will quiet down until 3000 miles. It worked for me before IIRC

Anyway, about a mile in to the drive, I came to a stop sign and I had my
window rolled down so I could hear the motor. I noticed that not only were
the lifters ticking, but I could hear a hammer-like
"wump!-wump!-wump!-wump!" type of noise coming from the engine that scared
the crap out of me. I turned the motor off and waiting about 15 seconds
before starting it again. It fired right up and the noise was gone. It
didn't recur for the mile home or the subsequent 5 minutes of idling in
the driveway.

I've had this exact noise happen to me once before (earlier this week)
right as I was pulling in to my parking space and after I shut off and
restarted the engine the noise was gone. In the 3.5 years that I've owned
the car I never heard that noise before this week. I've heard my
engine knock before, at least I'm pretty sure thats what it was (when I
had my ign advanced to ~10 deg, just to see what happened) - a "gutta
gutta gutta" noise when I was on the throttle accompanied by low power.

It didn't sound like knocking- it sounded more like noise that would
result from a lack of oil pressure. I'm not certain that that is what the
problem is, though. I'm confused about why turning the car off and on
again would make any difference..

Anybody heard their motor make this kind of noise before?

-Toby