2005 Ford FreeStar Trouble Codes

We have 2005 Ford Freestar with a 3.9 L V6, with 35,000 miles. It has started running rough recently. The check engine light came on as well. I scanned it with my little Auto Xray EZ Link. Quite a few codes came up. About half were undefined. They were : P0053 undefined, P0059 undefined, P0132 o2 voltage high B1 S1, P0152 o2 voltage high B2 S1, P0158 o2 voltage high B2 S2, P2196 Manufacturer Specific Powertrain, P2198 Manufacturer Specific Powertrain, P0300 Random Cylinder Misfire. I replaced the plugs, and a bad oil pressure switch.Cleared the codes. The check engine light came back on and engine began to misfire again, intermitently. Can someone tell me what the undefined and manufacturer specific codes mean and what i should look at next. Thank you.

We have a 2004 with 99,000 miles on it and this happened to us just yesterday. The oil and coolant seem fine, I haven't checked the codes, but will follow this thread closely, my uncle is a general manager at a ford dealership, I'm going to ask him to ask his guys about it, if I find a fix, I'll let you know, good luck.

P0300 - Random misfires

You need good Air, Fuel, ignition, and exhaust for horse power!

1) Replace Air + fuel filters
2) Clean MAF/IACT sensors.
3) New upstream H02 sensors?
4) Smoke test for unmetered air leaks.
5) Fuel pressure test
6) Load Test on both Battery and alternator.
7) Catalytic converter back pressure test.

If DIY for example-
Do a Google ''Youtube auto how to clean MAF sensor''

Also check the coil pack for cracks (on the bottom). A crack will usually indicate a bad coil.

I found something interesting. 06 Freestar 3.9 V6 180K. has been missing off idle for a long time. replaced plugs, wires, coil, had an analysis by Ford dealer - found nothing; replaced ERG because of P0400 -- no change; got worse with P0304; took off plastic intake today (didn't need to drain coolant as suggested in Ford shop manual); finally found something broken.
The aluminum bottom intake has a carb looking flapper valve on a shaft on one of two intake channels per each cylinder. One shaft was frozen open, one shaft was frozen closed. Each shaft controls three of these valves. An actuator controls both shafts via linkages with plastic seats. The linkages had fallen away; the plastic seats were broken or gone. The shafts loosened up quickly without much effort, but it was obvious that the linkages had come loose some time ago. Will go to Ford dealer and get the replacement plastic seats and put things back together. This looks like the obvious problem with one side of the engine hesitating due to slow air flow. These valves probably don't normally open until there is enough engine RPMs and demand for power. Have looked all over the Internet for what has been happening to folks with this engine series and never found on the internet what I found today.
Update: You can find about this under IRMC Bushing Fix. Plastic seats are Dorman 47099 and can be replaced without taking off the plastic top intake. You can see the linkages operate by looking at the far side from the throttle body and reving the motor a little. So.. I fixed the linkages and put everything back together. Runs better, but still has a noticeable miss at idle and gentle accelerations. Tried some injector cleaner and thought that it cured the problem. I noticed that the engine idled smoothly after a 25 mi. run. But the miss seems to have returned. No check engine light since I made the last fixes. Stuck for now. Am investigating how to test the injectors.