TROUBLE CODE

I read the check engine code on my '98 B3000 2WD auto
code 401 - "exhaust gas recirculation flow insufficient detected"
anyone got any insights into this, like where to look for a problem.

Bad EGR valve.BJ

there's a bit more to that system than just the egr... being your truck is ford based, seard some ford-trucks sites..... seems to be plenty of discussion on it and what to check for...

i'm also going with bad/plugged EGR

i received a similar code on my 01 4.0 SOHC ranger. but it was actually the sensor itself. on the SOHC 4.0 rangers, the sensor is some plastic crap, easily gets melted by the exhaust it is "sensing". doubt the 98 3.0's had that problem. but the EGR is where the recirculated gas passes through, if it is plugged, it'll throw a code.

pretty much all it is doing to your truck now is that you aren't getting as much gas mileage and the excess gas isnt getting recirculated, thus relying on the Catalytic converters to burn those unburned fuel, all 3 or 4 of them, i forgot how many cats the 3.0 has. overtime, the 1st cats on each side will get plugged quicker

Having been arounf Fords about as long as I have been around Mazdas when a Ford throws a 401 code u might as well replace the EGR valve and fugetabotit.Sure the system is complex but that code indicates little or no air going thru the valve. Not much else to look for.Mark is right on when he says the next thing to go are u r cats.BJ

should there be a vacuum, at idle, when you pull the line off the top of the EGR valve