1996 Chevrolet Lumina

Engine Performance problem
1996 Chevy Lumina 6 cyl Two Wheel Drive Automatic 176000 miles

My 1996 Chevy Lumina's Service Engine Soon light is on.

Computer code P1406 and P0401 (Autozone)

I had the EGR Valve replaced two times in two weeks.

The mechanic's only suggested solution was remove the intake and scrub with a wire

I also had the dealer's service center look at the car. They suggested that a fuel additive might help clear the blockage. I've tried the additive and it is not working.

The car runs fine, could they be overlooking something.
August 27, 2009.

Most likely you have an EGR port clogged with carbon build-up, common on these 3.1L and 3.4L engines. Remove the throttle cable bracket and look down the PCV tube hold on top of the intake. Also check the PCV operation and ensure its not sucking oil out of the valve cover. If it is, oil will fall on top of the EGR port. May be easier to remove throttle body to clean carbon build up.

Aug 27, 2009.