Hi,

Here's the story. I bought a 98 Legacy with only 40K miles, but with
the "check engine light" on, from a dealer in New Jersey, got on the
turnpike, and it stalled at the first tollbooth. It started fine, but
the engine sounded like a lawnmower, was shaking terribly, and had a
fraction of the power it was supposed to. I brought it back to the
dealer, he started it up, and it was fine. We later figured out that if
the car is doing this, you can turn it off, let it sit 5-10 seconds,
and when you start it up, it's fine.

Sometimes, the car will start running badly, shaking etc, without
stalling first. Always, though, it's when the RPMs have gone from high
to low pretty quickly, like when stopping, or shifting into neutral
between gears. However, it doesn't always happen, so it's difficult to
replicate.

He had me bring it to a mechanic, who replaced injectors and the Idle
Air Control motor. When I picked it up, the CEL was off, I thought
everything was okay. First time I get on a highway, though, and slow
down due to traffic, it stalls, I restart, it sounds terrible and has
no power, and the CEL is back on.

The dealer had me bring it to another mechanic, who took out the EGR
valve and told me to drive it for a week or two. If the car doesn't run
badly, the EGR was the problem. It ran very good after this for several
days, but occasionally stalled. Then, one day it stalled and shook and
had no power. It did this a few times, but not near the frequency it
had been when I first bought it.

Then, I took it on a 100-mile trip, and it started stalling almost at
every stop sign, sometimes running badly afterwards, sometimes not.

As it is now, I'm taking it back to the second mechanic, who will put
in a new EGR and then do the "next thing".

What could possibly be wrong with this otherwise wonderful car?