I own a 1996 Accord EX with 4 cylinder VTEC engine with
137K miles on it.  I mostly drive this car in city and when I drive
it faster than 55 mph, the check engine light turns on (but not always).

OBD code reads as P0401 - EGR valve insufficient flow

Whenever it turns on, I clear the code and it does not appear
again unless I take a freeway.  I haven't found any unusual
symptoms with the light on.  Since I drive only about 200 miles
per month and do not want to spend hundreds of dollars repairing it,
I just clear the code whenever it comes on and it happens about
2-3 times per month.

Recently, I discovered that there is an extended emissions warranty
which applies to 1996 Accord (and some other models).

http://www.epa.gov/compliance/resources/cases/civil/caa/amerhonda.html

So my questions are

1) Is this problem covered by this extended emissions warranty?

2) If it is not, would it damage the engine if I keep clearing the code
and do not fix this problem?

For question #1, I just called the dealer and was told that they can
say for sure after doing diagnosis on the vehicle.  I would like to
know because I need to pay the diagnosis charge if it is not covered
by the warranty.

Thanks in advance!