1997 Explorer Sport. P0174,P0133,P1131,P0153 Codes

[evadsec]

I have a 1997 Ford Explorer Sport trac two door 4x4 4.0 SOHC, after I bought it the check engine light came on I took it to a auto parts dealer scan it and 4 codes come back the p0174 (fuel system too lean cylinder bank 2) p1131 (lack of ho2s 11 switching ho2s signal low input), p0133 (ho2s 11 circuit slow response bank 1 sensor 1), P0153 (ho2s 21 bank 2 sensor 1 circuit slow response) also the the truck isn't running right , rough idle it dies at a stop light or a stop sign after a little bit of time or in a McDonald's drive-thru waiting too long it starts to putter out if I give it gas it will stay running. I replaced the PCV valve and the plastic T and the two vaccum hoses that run to the intake, also has a rolling idle sometimes but not all the time like it's searching for its idle position, I cleaned the mass airflow sensor I cleaned the throttle body, I clean the IAC and then I replaced the IAC with
Another one that was better and I also cleaned it, vacuum hose that ran to the PCV valve was caved in that ran to the right side of the intake if you were looking at the engine from the bumper that's why I decided to change PCV valve & its 2 vacuum hoses. And yet it still Dies. I called underneath the check out the O2 sensors the downstreams, and the passenger side Downstream is so loose that I can hand untighten it, I put thread lock on it I've attempted to tighten it down on numerous occasions I can't get it tight down and keeps coming loose again., I'm not sure if the passenger side Downstream will cause a vacuum leak 4 my truck is dying, I left it be for the time being and Focus my attention on the fuel filter which looks like it's never been changed so I picked one up and I'm going to put it on very soon possibly today but it's raining right now. Any suggestions would be much appreciated thank you

Oh and when I got it I also replaced, I put a brand new air filter and put a brand new belt on, and oil change.. and I didn't mention I also to the best of my ability checked all my hoses for vacuum leaks I didn't spray starter fluid and I don't have a fog machine but I inspected my hoses as best as I could without needlessly replacing them except for the PCV valve vacuum hose that goes to the intake that was obvious it was caved in.

 

[J_C]

You could pull individual vac lines off the intake and plug them one at a time, or pinch those soft enough that pinching is possible (though old rubber can be damaged from pinching) trying to further rule out vac lines.

Check fuel pressure with a gauge on the fuel rail before changing the fuel filter - it may eventually need a new filter but since it isn't running right, ruling out the fuel pressure with a gauge is faster and rules out the pump and fuel pressure regulator too.

Otherwise, if no fuel pressure issue then I'd assume you need new intake manifold gaskets.

Looking at the error codes, you might need a new bank 1 upstream O2 sensor. As far as the loose downstream sensor goes, I'd wonder if the prior owner cross-threaded it and it's going to be hard to get it to stay tight.

In that case I'd buy a new sensor for downstream either way, and put some exhaust sealant on the threads, and let it sit for an hour before idling the engine for a while to cure the sealant... hoping that this lasts until the day comes that you need the pipe replaced. I mean a sealant like the following unless someone else knows of a better product: https://www.amazon.com/Permatex-80335-Muffler-Tailpipe-Sealer/dp/B000BOAZM8

Could be that you need a new bank 2 upstream O2 sensor too, it'd make sense that they're both in about the same state if the same age... or you could probe for voltage going to them to confirm that they're getting power and just giving a bad reading, but personally I would assume there's an intake manifold leak, replace that and clear the codes then see which codes come back before replacing all but the one loose O2 sensor which I would go ahead and replace now just because it won't tighten down.

You might inspect the threads on it, maybe you got lucky and it's mostly the thread on it damaged and not the pipe fitting. In other words I'd try to thread in a new one gently and if it seems to thread, skip the exhaust sealant but if it's sketchy, put the exhaust sealant on the threads and be careful to tighten it just enough to seat and let the exhaust sealant do the rest.

 

[evadsec]

Thanks for that last night, I also started replacing the plug s and wires, they look like the originals I was kind of worried about that that's why I took one out to inspect the plug. They were bad I checked the gap on them there were huge at like 74. I couldn't believe those plugs are in this so I'm replacing all plugs and wires, intake gasket, I took carbon choke cleaner last night while the engine was running and hit all the vacuum lines to see if it would bog down any and it didn't I sprayed it all over the engine and I could not find a vacuum leak. I think the hoses are fine and like you said I'm going to go with you on the intake gasket, then I'm heading to a friend's house right now to check fuel pressure, I'm going to pick up some sealant for the loose O2 sensor. The loose O2 sensor is my driver side Downstream, I also have an exhaust leak it might be coming from the manifold because I took the two driver side plugs out I can see the exhaust manifold gasket I think it's metal but thank you for your reply I'm going to change my gaskets like you say

 

[evadsec]

You could pull individual vac lines off the intake and plug them one at a time, or pinch those soft enough that pinching is possible (though old rubber can be damaged from pinching) trying to further rule out vac lines.

Check fuel pressure with a gauge on the fuel rail before changing the fuel filter - it may eventually need a new filter but since it isn't running right, ruling out the fuel pressure with a gauge is faster and rules out the pump and fuel pressure regulator too.

Otherwise, if no fuel pressure issue then I'd assume you need new intake manifold gaskets.

Looking at the error codes, you might need a new bank 1 upstream O2 sensor. As far as the loose downstream sensor goes, I'd wonder if the prior owner cross-threaded it and it's going to be hard to get it to stay tight.

In that case I'd buy a new sensor for downstream either way, and put some exhaust sealant on the threads, and let it sit for an hour before idling the engine for a while to cure the sealant... hoping that this lasts until the day comes that you need the pipe replaced. I mean a sealant like the following unless someone else knows of a better product: https://www.amazon.com/Permatex-80335-Muffler-Tailpipe-Sealer/dp/B000BOAZM8

Could be that you need a new bank 2 upstream O2 sensor too, it'd make sense that they're both in about the same state if the same age... or you could probe for voltage going to them to confirm that they're getting power and just giving a bad reading, but personally I would assume there's an intake manifold leak, replace that and clear the codes then see which codes come back before replacing all but the one loose O2 sensor which I would go ahead and replace now just because it won't tighten down.

You might inspect the threads on it, maybe you got lucky and it's mostly the thread on it damaged and not the pipe fitting. In other words I'd try to thread in a new one gently and if it seems to thread, skip the exhaust sealant but if it's sketchy, put the exhaust sealant on the threads and be careful to tighten it just enough to seat and let the exhaust sealant do the rest.

So, I replaced Bank One sensor 1 & Bank 2 Sensor 1 & the lower intake upper intake gaskets upper intake gaskets last night, I also replaced the spark plugs and wires. Here's some pictures of what it look like