Well I fixed my p0401 code about 2 months ago. I've gone about 4000 miles since then. Last might when I came home the check engine light was off. Started it This morning and it was on. I used my code scanner and it showed p0402 excessive egr flow. The only thing I can think of is a leaking gasket.

Anyone have any suggestions. It's a 98 f150 with the 4.6.

Thanks.

 

A leak anywhere in the tube to EGR, dpfe hoses, EGR seat or a leaking/stuck vacuum gate valve that applies vacuum to the EGR will result in the 402 code.
The 402 test is done right after startup when exhaust pressure is forced into the tube with the system closed.
If the DPFE sees a lower pressure from a leak, the code is set for ''excess'' flow.
That's all there is to it.