misfire at idle

I have a 2005 ford escape 1 owner 3.0 v6 with 80.000 miles on it showing no codes. with a misfire at idle. it has a new computer, new coils, and plugs.
i also replaced the lower and upper intake gaskets. and a new iac, the car runs great after idle with no misfire and seems fine. the cats seem good. the car runs better when warm but still misfires.

i am not sure what to check next.

Misfire on all cylinders or on a specific cylinder?
What are the misfire-counters tell you?

If specific cylinder ----> Compression Test

Thank you for your reply.
my engine is a v6 and the right side is by the firewall. I can't get to the back 3 plugs without removing the Intake. and thats a bear!
I have 2 code readers and they show no codes or i/m problems. one reader is Bluetooth and the other is a foxwell nt201.
I had the intake off before and put in new plugs, and cops.( still no change).the old plugs looked normal. I also put in all intake gaskets.
I used an old cop and plug then put it on (1 at a time) cyl. 4 , 5 , and 6. They all had great spark. The motor is not using any oil.and has never been overheated.
Could the cat be just dirty enough to cause this but not send a code? the numbers on bank 1 and 2 look good but the front lower is wavering just a bit. Thanks, caje70

Not trying to doubt you, but what is the indication that you have a miss at idle? A noticeable roughness? Vibration?

If you truly have some kind of miss with no trouble code, then it'll likely show up in Mode $06 data. The wiring diagram says this vehicle is a CAN network, so you'll likely find the misfire counts under TID $80 or 83. Check all six to see if any have been flagging misses currently or in the last 10 trips. Try not to clear the codes more than needed, as this will reset the misfire counts.

Could the cat be just dirty enough to cause this but not send a code? the numbers on bank 1 and 2 look good but the front lower is wavering just a bit. Thanks, caje70

Which numbers are you referring to, exactly? Fuel trims, cylinder contribution?

A plugged cat is definitely possible on this engine. But, it usually only occurs at higher mileage, after it's had a couple coils fail. A plugged cat will also show up more at higher engine loads as a low power complaint, not a rough idle.

The o2 sensors are the numbers I was talking about. the car did have a misfire and an ecu go out last year. Ford said it was the ecu and would be $1700 for the ecu. I could not do that so I got my computer rebuilt. then I installed new oem coils and plugs. The intake gaskets were replaced with felpro. after all, was installed I had the miss problem when cold and looked at the cats. one of the cat.s had a good reading on the top o2 sensor but the bottom o2 sensor was jumping MVolts.s just a bit. I replaced the o2sensor but no change. Before the ecu went out you could not tell the car was running at a stop light it was that smooth running. after all the above it has a steering wheel shake and you can feel it through the seat when at idle. it idles better when it is hot.
I did clear the ecu a few days ago(it had no codes). after that, I ran it sitting till warm-up plus had a few trips to town on it. The $TID80 and 83 numbers on cyl 1 through 6 show no misfires. If I can't find the miss soon I will just take it to ford. But as a retired firefighter, I hate to do that. It's just way too much $ to go there. anyway, thanks for your help! I was hoping someone would have had this problem and had fixed it. I will keep at it a bit longer maybe i will find it. Thanks for your help, Phil Oh also the car runs great at highway speed.just has a rough idle