Drae
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I need a little direction with my 03 Expedition 5.4 2V with 198K miles. Maybe someone has experienced something similar because it seems rare to have both P0171 and P0175 at the same time. This also triggers a misfire on cylinder 6 and it will give the P0316 also which is 1 or more misfire shortly after start up. The engine will Idle rough but will smooth out with rpm.
First of all it started as only P0171 so I checked for vacuum leaks first and found the vacuum hose to the PCV valve was soft and collapsed. I replaced that part of the hose and put a new OEM PCV valve in and nothing changed. I inspected all vacuum connections and sprayed carb cleaner for idle changes and nothing changed but it triggered the P0306 and P0175 codes afterwards. I pulled the number 6 coil and plug out to check and plug was normal with no fouling or fuel smell. Then I swapped a known working coil to see if it changed anything it didn't.
Next I changed all 4 O2 sensors first with no change. Then I found out the MAF readings were reading way too low and changed it also. The MAF reading is good now but there isn't any change in idle. The STFTs are way off on both banks so just started unplugging injectors and ignition coils on both banks to see if idle changed. All of bank 1 injectors and coil packs made tbe ifle a little rougher. Bank 2 coils and injectors did nothing at all. I found 1 video where a guy said he had both codes also and started with the MAF sensor. It didn't resolve his issue either and it ended up being a timing job that resolved the issue.
I've owned it 10 years now and it had around 102K miles when I got it so I doubt it's been done. It's had the 2 second chain slap on startup here and there for a while so it's possible I need to this as well. The only thing stopping me from just jumping on the timing job is the bank 2 ignition and fuel injector problem.I know timing can affect this fuel and spark but I'd hate to do the timing job and find out it was something else after doing that much work. It's literally the last resolution if I can't find anything else. Some known issues that's been there for a little while is a small exhaust leak in the Y pipe connection and one of the catalytic coverters had a rattle for a while but went away. No loss in power as I've been through clogged cats in this vehicle before and know how that feels.
I apologize for the long post but trying to give as much info as possible for some suggestions.
First of all it started as only P0171 so I checked for vacuum leaks first and found the vacuum hose to the PCV valve was soft and collapsed. I replaced that part of the hose and put a new OEM PCV valve in and nothing changed. I inspected all vacuum connections and sprayed carb cleaner for idle changes and nothing changed but it triggered the P0306 and P0175 codes afterwards. I pulled the number 6 coil and plug out to check and plug was normal with no fouling or fuel smell. Then I swapped a known working coil to see if it changed anything it didn't.
Next I changed all 4 O2 sensors first with no change. Then I found out the MAF readings were reading way too low and changed it also. The MAF reading is good now but there isn't any change in idle. The STFTs are way off on both banks so just started unplugging injectors and ignition coils on both banks to see if idle changed. All of bank 1 injectors and coil packs made tbe ifle a little rougher. Bank 2 coils and injectors did nothing at all. I found 1 video where a guy said he had both codes also and started with the MAF sensor. It didn't resolve his issue either and it ended up being a timing job that resolved the issue.
I've owned it 10 years now and it had around 102K miles when I got it so I doubt it's been done. It's had the 2 second chain slap on startup here and there for a while so it's possible I need to this as well. The only thing stopping me from just jumping on the timing job is the bank 2 ignition and fuel injector problem.I know timing can affect this fuel and spark but I'd hate to do the timing job and find out it was something else after doing that much work. It's literally the last resolution if I can't find anything else. Some known issues that's been there for a little while is a small exhaust leak in the Y pipe connection and one of the catalytic coverters had a rattle for a while but went away. No loss in power as I've been through clogged cats in this vehicle before and know how that feels.
I apologize for the long post but trying to give as much info as possible for some suggestions.
