You need to run the mode 6 test in Forscan to identify which cylinder(s) are misfiring. There is other data that it can report that will help you diagnose this in a structured way.
I bought '05 DOHC with a warm only misfire. Dealer cut $200 off I took it with the misfire. I drove it 180 miles home with the misfire which was worse when sitting in traffic but no so bad at road speed but still did it a few times. Used the code reader that I had as in the picture and used the "pending code" feature and it was #3. I switched #3 and #6 and the misfire followed the COP. I put a JY coil on it and no more misfire.Can't find a solution despite a lot of posts on this topic. Does anyone know something new besides what I've checked/replaced; plugs, vacume lines under hood (because it only happens afer heat soak, I'm sure it's not vacume behind firewall), EGR gaskets, broken ignition coil connectors, one bad coil. Smoke test reveled only very tiny smoke leak when both hot and cold. NO OBDII codes currently present. This model does not have the vacume line that rots which runs under the intake. No visual cracks on any plastic parts. Misfire does NOT happen when cold or on short first drive of the day. When it sits for 10 or so minutes after that short drive, it begins misfiring and generally clears when acceleration is increased dramatically. (that would seem to indicated a vacume leak, but again, I've replaced many lines and checked all others. Thanks
There's a video on youtube about the lower intake manifold gaskets causing misfires only when warm. Spray carb cleaner while running to test.As the coils heat up they reveal their weakness...
Fuel trims would be a eliminate that issue, for any vacuum leak.There's a video on youtube about the lower intake manifold gaskets causing misfires only when warm. Spray carb cleaner while running to test.
Those are phantom misfires rather than actual ones, plus that tends to happen more when the car is idling. OP didn't specify either way though.There's a video on youtube about the lower intake manifold gaskets causing misfires only when warm. Spray carb cleaner while running to test.
You're right. I misremembered and the symptom from leaky lower intake manifold was rough idle when cold, not misfire when warm. The same guy did a video with the same car where they had misfire when warm due to coil on plug issue.Fuel trims would be a eliminate that issue, for any vacuum leak.
Pic of what feels like misfire, no code, no pending code. Ford Tech told me this is common.Those are phantom misfires rather than actual ones, plus that tends to happen more when the car is idling. OP didn't specify either way though.
Most readers will read fuel trims. At idle +/-10% is fine. PIc my '04 Sable wagon after fixing leak at the EGR to intake. Was ~+20% before and only issue is bad cold idle. No codes.Thanks to all the suggestions. I've had it all apart, (manifold off, COP's off, etc) and checked for leaks, cracks in hoses and all the visual stuff I could. I'm going to do some extensive driving and looking at fuel trims next. I don't have Forscan so I can't do mode 6 tests with my scanner. Also tested resistance on all the COP's and they're consistent. I had replaced a bad one some time back and the new Bosch one reads a bit higher.
An ELM327 is $20 or less and Forscan is free or ~$5.I don't have Forscan so I can't do mode 6 tests with my scanner.