I’ve. Changed what I thought was a bad coil but still misses. Cld it be another bad coil? R is it something more??? I also change the cat converter but didn’t help. Guess I need to hook up to a computer.

this only happens intermittently btw.

 

Flashing cel is a misfire bad enough to damage the cats. Get a scanner on it and see what it comes back with

if you replaced only coil which one and what made you replace that particular one?

Which eco - the 3.5?

 

You shouldn't be driving it with a flashing check engine light. It means there is something wrong that could cause further problems, like destroying a catalytic converter. You need to get the OBDII codes read instead of guessing what the problem is. Each cylinder has a coilpak, and any of them could be bad. Without knowing what the codes are you are just guessing, and throwing money away.

 

Happened to my 3.5 EB in my F150. Bad O2 sensor. Replaced and have driven it 20k miles since with no issues...

 

YOU CANNOT CHEAP OUT AND GUESS REPAIR THESE TRUCKS.
It cost you twice as much in the end when you don't know what your doing.
Find the cylinder in fault first, then fix the issue. It's called diagnostics!
Then if the Cat is ruined, a code will be set for that failure a 420 or 430 code, replace it at a hundred times the cost of fixing the missing cylinder that caused the CAT to fail, on that bank.
Ox sensors do not cause these issues.
The engine will run fine even if the Ox sensors are both disconnected. All that happens is the fuel runs a >bit rich< because the computer substitutes a [fixed fuel table value], until the sensors are working again, and fuel mileage takes a hit, no misfires, so the engine does not run Lean and do damage from overheating. There is no reason why Ox sensors would be allowed to do damage.
Using a Scanner looking at live and stored data mode 6, tests 80 to 83 has the misfire records for every cylinder. even if there is no code or CEL set.

 

Hello, fellow Louisianian!
Are there any engine codes?

 

Pay the troubleshooting fee at ford and figure out whats wrong----either pay them to fix it or take it back and fix what they say!!!

 

How many miles on it? My wifes expedition with the 3.5 eco was having a similar issue. If you haven't read the check engine light codes, you are just throwing stuff at the wall. in my case i had a few cylinders missfiring and a p0300 random misfire. at 68k miles. it just needed spark plugs. have the codes read and let us know what they say

 

O2 sensors cause misfire: https://thecarmoguls.com/will-bad-o2...cause-misfire/

Either that, or it was a miracle when the ford dealer replaced it under warranty and my cylinders stopped misfiring..

 

You had something else going on.
Ox sensors only signal the PCM for the next fuel injector pulse-with to be set for the next cylinder on that bank to fire.
Yes you likely had a Miricale based on circumstance only.
The world does not run on Miracles.
As I said, the engine will run with them disconnected and can easily be proven.
Good luck.