I have a 98 Ford Windstar with the 3.0 liter engine and high miles, about 178,000. There's a P0401 code -- insufficient EGR flow detected -- that I just can't make go away. To make a long story shorter, I've replaced the flow sensor, the EGR valve, and the EGR solenoid. The hoses look fine and if I pull a vacuum on the EGR valve at idle, the idle drops and roughens but the engine doesn't stall. The sensor voltage at idle (or with key on engine off) is about 1 volt (it's the new plastic version). With the EGR open at idle the sensor signal rises about 0.05-0.07 volt, and during some limited testing while driving, the sensor signal goes as high as about 1.5 volts. From some of the other test data I can pull from the computer, it fails two diagnostic tests: the EGR Lo Flow is about 3.5 - 4.5 in H20 with a minimum 6.0, and the EGR open duty cycle is 88-89% with a maximum of 80%. But those sound like the symptom and not the problem. Is it possible the intake manifold is partially restricted where the EGR valve connects? What else am I missing here? Thanks for your help! Randall

I am looking for the firing order for a chevy cavalier 2.2 1994. this engine does not have a distributor, if that helps....thanks