I have a 98 4.2 f-150, that has codes for all 4 o2 sensors, can they go bad at once, black smoke comes from the tail pipe, runs better if it has a vacuum leak, or can the map, sensor be bad?
Daves944 knows what he is talking about, u need to find the root cause of this problem, which is a problem any of th following can cause this, MAF, Intake leaks, engine conditions like low compression and many other things, the O2 codes are a Symptom not the problem, you may also have a wiring harness problem, check the harness connectors to the O2 sensors, look for exhaust heat related wiring damage, look for corrosion in connectors.
Po171 and 174 is leak in vacuum such as intake gaskets or crack if u have a plastic intake manifold.....2nd also fuel pump can cause this to codes to appear so check pressure on the pump ignition on 35... when started up or at idle 50up...if it drops below 30 its time for a replacement...
You can very easily get codes that you may interpret as bad O2 sensors but have nothing to do with them. What are the codes? A Map sensor is a possibility but the coolant sensor also has a large influence on fuel control. If you have access to a scanner you should check operational values for all the sensors. The coolant sensor should read ambient air temperature in the morning before the engine is started and then work it's way up to 195 F. The upstream O2 sensors should be reading about .9 V when they're hot and mixture is rich (black smoke), try driving them lean (.1 V) by creating a vacuum leak. If your rich running condition continues it will destroy the O2's but typically O2 sensors don't have enough authority to drive the system balls rich.
Code numbers?
Wow! I've never seen so many O2 codes in the same place at the same time. :-)
First of all, I suspect some of these were created recently by accident or diagnosis. When you see codes (1152, 1132) for sensors that are locked rich but not switching, it usually means the sensors are good but not switching because fuel is not being controlled.
I would have a very close look underneath the front of the intake plenum. There is a PCV hose that rots out right as it does a 90 degree bend and attaches to a nipple at the front of the intake manifold. Check this, replace the hose end if necessary, clear the codes and drive it for 15 minutes. This hose end that I'm talking about is hard to see and hard to change, you kind of have to poke your fingers through the front of the plenum. It's kind of a brail job as you can't see it very well. Sometimes you can hear them hissing with the engine running as they leak vacuum.
Repost with fresh codes and if the hose end was bad.
Hey thanks for that, e-wiz, my boss usually just says I'm not as dumb as I look. :-)
P0171 and 174 are lean codes likely caused by the P0302 which is a misfire code. When the engine is misfiring it is always dumping oxygen into the exhaust stream so the sensors always see it and set a lean code. This happens despite the fact that the engine is probably running very rich because the computer is trying to correct what it thinks is a lean condition. You must correct the misfire, try a set of plugs and then track down the bad coil pack or ignition wire if the plugs don't correct it. I say coil pack or wire because I don't know which system you have, could be either one.
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ok, it is a 97 ford f-150, 4.2, it has 8 codes; p0135, p0141, p0151, p0155, p0161, p1132, p1151, p1152, it has had new plugs, wires, coil pack, egr valve and new fuel pressure regulator, dosen't stall now, but still has these codes now.
Hi, ok it is a 97 f-150, 4.2 I have 8 codes; p0135, p0141, p0151, p0155, p0161, p1132, p1151, p1152, it has new plugs, wires, coil pack, fuel press. reg, and new egr valve, won't pass emissions
Code PO171 - lean exhaust bank 1
Code PO174 - lean exhaust bank 2
Code PO302 - oxygen heater circuit
What does all this mean
I very seriously doubt this, u had better get this to the dealer and have a proper diagnosis done or u will waste $300+ on un needed parts.
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