pfSense CARP - WAN failure on firewall

Solution 1:

i would try running tcpdump on your gateway 172.16.1.254 (or "debugs" on cisco routers), to make sure traffic is actually getting out correctly, and not being blackholed via route loop or otherwise. i dont think it would be the firewall rules, but you can enable debugging on each rule to make sure and tail -f logs. if a rule is blocking, it will show in logs

also, the manual outbound nat may be breaking things, so i would check that too. you can also drop shell on the freebsd box (pfsense) and run tcpdump there as well. lastly, you can "backup" your pfsense config via xml file, and then factory reset. add / change one thing at a time, until you replicate the issue. restore config from xml file and fix culprit.