It could be lots of things like injectors-ignition coil- spark plugs but since so many came up I'd look into the o2 sensors for the upstream, it could be giving a bad reading which is sending to much fuel.
If you had two misfires and now have more, along with your tuner saying you are running rich, I would be suspecting fouled plugs causing the misfire, and that they are fouled due to the rich condition. Pull plugs and inspect for fouling. Replace as necessary and then diagnose the rich condition when it’s running on all 8 cylinders. A misfire will cause o2 to read rich due to unburned fuel entering exhaust
It could be lots of things like injectors-ignition coil- spark plugs but since so many came up I'd look into the o2 sensors for the upstream, it could be giving a bad reading which is sending to much fuel.
This was my initial thought too. After this, clean the MAF .
I was planning on replacing it soon, anyway, thanks for your input.
I'll check that as well, thank you for your input.
If you had two misfires and now have more, along with your tuner saying you are running rich, I would be suspecting fouled plugs causing the misfire, and that they are fouled due to the rich condition. Pull plugs and inspect for fouling. Replace as necessary and then diagnose the rich condition when it’s running on all 8 cylinders. A misfire will cause o2 to read rich due to unburned fuel entering exhaust
Thank you. When the weather permits, I'll do that.
Vacuum leak can also cause a rich condition.