Yo Scotty how’s it going hope your doing good. My names Abel Ruiz from Pomona CA I just registered my account first time here to ask a question. I’ve have a 1998 Ford F-150 4.6L 2WD with a p0401 code for like ever I’ve replaced my egr valve, egr position sensor, egr vacuum solenoid, MAF SENSOR, took throttle body off cleaned it, also replaced valve cover gaskets, and exhaust manifold gaskets. I did the work my self because mechanics out here are expensive and aren’t reliable. the code is still there and I was hoping you had an idea of what it can possibly be maybe I missed something?
I agree with MMJoe on this one. If all the hardware is new and connected properly, your egr system has to be crudded up with carbon and needs to be cleaned out entirely. By the way, did you clear the code after the work was done?
Please post the entire code. Not just the number.
P0401 Insufficient EGR Flow
See the causes and possible solutions on this page:
https://www.obd-codes.com/p0401
You could have a vacuum leak, or the EGR pipe is caked in carbon.
