4.6 w/ 68,000 miles. Check engine light came on couple weeks ago but ran fine
(Inspection due this month / was waiting 'till then)
Yesterday begins running rough / check engine light now flashing under load
Scanned these codes (Actron OBD II)
PO172 bank 1 rich
PO175 bank 2 rich
PO307 cyl 7 misfire
What do I neeed to do to correct? Did it foul #7 plug running rich? Why was it running rich?
Any help ?? Thanx

 

Ahhhhhhh, running rich....
I can't tell you how long I've been dealing with this problem. This is what I've been told. I've done all but the last thing on this list.
Clean your Mass air flow sensor with Electrical parts cleaner. (not carb or break cleaner)
If you use an aftermarket cold air intake system, take it off.
Check your resistance on the Mass air for proper conductivity.
Check vacuum lines for leaks.
Check your intake manifold for a leaking gasket or cracks.
Since both banks are lean forget the o2 sensors, since the odds of both of them failing at once is slim.
Someone mentioned the egr, although I don't know why this would cause the problem.
Finally, replace your intake manifold.
Start with the cheapest fix and move on.
I hope you have better luck than I have had.

 

Ok, everything u just posted is for a LEAN condition. That would be great, but he has a rich condition..... Check the Fuel Pressure Regulator on the fuel rail. Pull the vacuum line off while running and watch for fuel to leak out of the regulator. Check fuel pressure too. Higher then spec. fuel pressure can cause to much fuel to be shot through the injector. Also inspect the ECT sensor and if possible watch the PIDs for that sensor. A faulty ECT sensor will read a very low negative number thus riching out the air/fuel mixture because the pcm thinks the engine is cold and it's trying to warm it up.

The #7 misfire could be a bad plug and the rich mixture is causing incomplete burn. It could also be a bad injector leaking to much fuel in or not enough. Pull the plug and check them over. If possible replace the #7 wire with a known good one and see if it fixes the miss. I don't remember if 00' had COP's yet. If so, you can just switch the #7 with another COP(like #6) and see if the misfire moves to that cylinder.

You can also check your O2 sensors by watching the PIDs and if they run constantly rich, try to lean them out manually. Disconnect a vacuum hose and watch for the o2 sensor to go lean(<0.3volts). If it stays permanantely(sp?) rich, you problably have a bad sensor.

 

Sorry about that... I saw bank 1 bank 2 and jumped to conclusions.