1999 Ford Explorer

Engine Performance problem
1999 Ford Explorer 6 cyl Four Wheel Drive Automatic

at times we have a rough idle upon startup after after a few minutes it will smooth out.
the ford dealer did a diagnostic and said we needed
an egr orlng/fuel rail gasket/ing. Oring/upper plenum gasket.
what I find odd is if I put a can of seafoam in the gas the vechicle will run fine for a couple of months then act up again.
if we try to drive while it is having a spell it misses and loss of power untill it smooths out.
any suggestions thanks
September 9, 2009.

I would start with the EGR. It can cause the problem. Also, it is something you can replace yourself. It is on the intake and is bolted on with 2 bolts.