I have a full size 1990 - 20 GMC Van. It has a very rough idle but is
fine once cruising or accelerating. It is my belief that this is a result
of the engine's EGR Valve not working correctly and/or a blocked in-line
fuel filter (the gas tank sending unit and filter have recently been
If someone has had a similar experience or knows how to remedy this
condition I would be greatly appreciative of their help!