Warning long post: For a year I've been trying to cure my intermittent rough idle and poor shifting/acceleration issues. My NAS 2003 Disco II 4.6 V8 w/ SAI has 87k on it. I have replaced all of the following: Plugs and 8mm magnecor wires, new Bosch MAF, new alternator, new hoses, water pump and viscous (engine runs at perfect temp at all times, no leaks), new serp belt and all pulleys, new PAS. I have cleaned the stepper motor and tested and cleaned the TPS, cleaned the purge valve and the breather valve, drained and refilled the tranny w/filter change, I have stripped down the top of the engine and replaced both intake gaskets, valve cover gaskets, numerous oil and filter changes (oil always comes out clean), I've done a sea foam treatment twice.
Never have thrown a code but still had intermittent rough idle (usually when warm) and the intermittent acceleration issues (intermittent because sometimes this thing runs like a rocket, even when warm and has power like a brand new 4.6) so I decided to just bite the bullet and replace all 4 O2 sensors. It ran great at first but after awhile started having the same symptoms. Then I realized what went wrong - months earlier, I stopped shy of replacing the valley pan gasket even though I knew it was leaking as it just seemed too hard for my skill level. Yesterday I realized that leak was sending oil into the top of the RH front O2 sensor plug. I opened up the O2 connector and sure enough, filled with oil. I blew it out, cleaned it with electronics cleaner, it is now bone dry and clean. I rerouted the cable so it is no longer in the path of the leaking oil from the valley pan but upon restarting and running it, first I get a P0174, P0150 and P1174 after the truck gets to operating temp.
P0150 Stoichiometric ratio outside operating band
P0174 Multiplication fuelling adaption (Max.) exceeded rich limit ‐ RH bank
P1174 Additive fuelling adaption (Max.) exceeded rich limit ‐ RH bank
If I erase them the P0150 comes up as 'pd' a 'PENDING' code after about 5 minutes. But the truck runs pretty damn good at speed but idles rough and I smell gas at idle.
Again, I cleaned all the oil off the connector and today I even replaced the RH front Bosch sensor with a new one and got the same codes!
I am totally stumped. I have checked thoroughly for vacuum leaks. None. As listed above, my MAF is factory Bosch and new, my purge valve is clean, my stepper is clean, the O2 sensor top connectors are clean and all 4 O2 sensors are new.
I started having these codes about a day after I replaced both rear O2 sensors with Bosch factory sensors, so I doubt something else went wrong at exactly the same time. I've tripled checked all connections. I have removed the O2 connectors from the side of the engine where they were mounted so they would not be in the path of the leaking oil. But I don't think that would cause it as I don't think the engine acts as ground for these things.
The front O2 sensors are Bosch Part # 15184 (spec for the 4.6)
Rears are Bosch Part # 15630
Any ideas? What can I check now? I have searched the forums and can't find any real solution to these three codes.
Never have thrown a code but still had intermittent rough idle (usually when warm) and the intermittent acceleration issues (intermittent because sometimes this thing runs like a rocket, even when warm and has power like a brand new 4.6) so I decided to just bite the bullet and replace all 4 O2 sensors. It ran great at first but after awhile started having the same symptoms. Then I realized what went wrong - months earlier, I stopped shy of replacing the valley pan gasket even though I knew it was leaking as it just seemed too hard for my skill level. Yesterday I realized that leak was sending oil into the top of the RH front O2 sensor plug. I opened up the O2 connector and sure enough, filled with oil. I blew it out, cleaned it with electronics cleaner, it is now bone dry and clean. I rerouted the cable so it is no longer in the path of the leaking oil from the valley pan but upon restarting and running it, first I get a P0174, P0150 and P1174 after the truck gets to operating temp.
P0150 Stoichiometric ratio outside operating band
P0174 Multiplication fuelling adaption (Max.) exceeded rich limit ‐ RH bank
P1174 Additive fuelling adaption (Max.) exceeded rich limit ‐ RH bank
If I erase them the P0150 comes up as 'pd' a 'PENDING' code after about 5 minutes. But the truck runs pretty damn good at speed but idles rough and I smell gas at idle.
Again, I cleaned all the oil off the connector and today I even replaced the RH front Bosch sensor with a new one and got the same codes!
I am totally stumped. I have checked thoroughly for vacuum leaks. None. As listed above, my MAF is factory Bosch and new, my purge valve is clean, my stepper is clean, the O2 sensor top connectors are clean and all 4 O2 sensors are new.
I started having these codes about a day after I replaced both rear O2 sensors with Bosch factory sensors, so I doubt something else went wrong at exactly the same time. I've tripled checked all connections. I have removed the O2 connectors from the side of the engine where they were mounted so they would not be in the path of the leaking oil. But I don't think that would cause it as I don't think the engine acts as ground for these things.
The front O2 sensors are Bosch Part # 15184 (spec for the 4.6)
Rears are Bosch Part # 15630
Any ideas? What can I check now? I have searched the forums and can't find any real solution to these three codes.
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