Please help before I burn my truck. 3 years of P1131 is enough!

[Tsestak45]

Hey so a really loooooong story but the short version is this: I have a 98 3.0L with 900 miles on it because I installed a remanufactured engines myself after the first one blew a pushrod through the block and the second one (installed by a mechanic who didn't crank down 19 different bolts that I found to be only hand tight) blew a head gasket and melted a piston. I finally said enough is enough and did it myself so that I knew every bolt was installed correctly. Before my original engine seized up due to a fin on the camshaft synchro breaking off (I now have a miniature heart attack every time I hear a belt chirp) I had my exhaust system completely leak free. Since then it has been the biggest nightmare of my life. Where the manifolds meet the downpipes there is so much pitting I can't get a good seal. When I first crank everything down the truck runs great until it gets warmed up. I will start having a ton of hesitation when starting from a stop. Eventually I will have hesitation after every gear shift, and ultimately after awhile I get the dreaded P1131! I've been working on this problem everyday after work for 2 weeks and feel like I have made 0 progress. Other symptoms my truck is having are as follows:

-Rough idle
-Hesitation whenever I shift gears for about 10-15 seconds then it goes WOT
- if I'm idling and I turn the wheel the power steering pulley makes it almost stall and whines (yes there's enough fluid)
- if I turn on AC my pulley starts chirping (again I immediately think camshaft synchro) and my AC clutch kicks on/off every 5 seconds (yes the system is up to pressure)
- hard starting
-engine shakes at idle
-behaves much better before it gets up to temp.
- when coming to a stop in neutral I have almost no power brake booster but if I leave it in gear as I stop the brakes are fine.

I'm hellbent that these can all be explained by an exhaust leak causing an O2 sensor to not work correctly but at this point I'm willing to admit I MIGHT BE WRONG! Please help if! I love my truck to death but lately I wanna take it to an abandon lot in Philly, set in on fire, and go on with my life.

 

[Tsestak45]

Sorry forgot. It's a 98 3.0L 2WD 5 speed manual with 210,000 original miles and around 900 with the newest motor

 

[RonD]

P1131 Lack of Upstream Heated Oxygen Sensor Switching – Sensor Indicates Lean – Bank No. 1

V6 engines have 2 Banks
Bank 1 is passenger side
Bank 2 is drivers side

1995 and up Rangers have upstream O2 sensors(S1) and downstream O2 sensors(S2)
Upstream O2s are used for fuel trim, so computer can maintain best MPG and 14.7:1 gasoline fuel ratio
Downstream O2s are used to make sure Cat Converters are working

O2s generate their own voltage once heated above 600degF
0.1v is high oxygen(lean)
0.9v is low oxygen(rich)

With V6 upstream O2 sensors the computer adjusts the Open Time for injectors on that one Bank/side of the engine to try and keep the voltage at 0.45v

Code indicates the upstream O2 sensor on Passenger side is showing low voltage regardless of what the computer tries
"Lack of.........switching"

O2s are THE ONLY sensor that have a time limit, 12 years or 100k miles, and they start to run out of chemicals that can detect oxygen and generate voltage, so voltage goes low and stays low

If you only have "lean" on one bank of a V6 engine then problem won't be something common to both banks, i.e. MAF sensor , fuel pressure, upper intake vacuum leak.....

Changing the O2 sensor or swapping passenger side to drivers side would be the first step, as it could be "false lean" because of failed O2 sensor

Yes, an exhaust manifold leak would suck in air so O2 on that bank would see that and send computer lower voltage, another type of "false lean"
But the leak would have to be between engine and O2 sensor, not at the end of "Y" pipe

Cylinder misfires on 1, 2, and 3 can also cause this code
When a cylinder misfires no oxygen is burned up with the fuel, so that oxygen is dumped into exhaust manifold and O2 sees it and lowers the voltage
So the code is not causing the rough running, the code is the result of the rough running

Is this a "new" engine or used engine?
2004-2006 3.0ls had exhaust valve recession issues

I would do a compression test just to rule it out, 3.0l Vulcan engines can burn exhaust valves and you can waste a lot of time and money on non-fixes if its a compression issue
Rough idle and low idle power(i.e. stalling with AC on) fits with compression issue and also P1131 if low compression is on passenger side

Pull out all 6 spark plugs and keep track of which cylinder each comes out of
Look at the tips
darker tips indicate cylinders with misfires, if its 1, 2, or 3 that would explain the code

 

[Tsestak45]

Hey man great reply with some useful info in it. It's a brand new remanufactured engines. The part that interested me the most was about the O2 sensor running out of whatever detects the oxygen. I'm assuming it still tests correctly for resistance on a multimeter (because why wouldn't it) but yet still not be able to function correctly. I'm gonna explore that further after work today and I will post my results. Also it's not at the bottom end of the Y-pipe it's where it meets the exhaust manifold on each side of the engine so it is before the upstream O2 sensors.

 

[RonD]

If exhaust leak is at the exhaust manifold then it will, 100% for sure, effect O2 on that bank of the engine

Yes, O2s wear out, only sensor that does, and if the engine was burning a non-gasoline/ethnol product it can shorten their life even more
i.e. burning oil or coolant

 

[Tsestak45]

Hey had a question and a bit more info. How do you know it's bank 1? When I looked up the code it didn't tell me it just said Bank 1 or bank 2. Also would the O2 sensor explain why it gets jerky when I let off the gas sometimes and also explain why the power brakes don't seem to work much when I'm coming to a complete stop with the clutch in?

 

[Tsestak45]

Also any recommendations on how to seal the joint where the Y-pipe meets both exhaust manifolds without buying new parts? I guess technically I could remove both manifolds and sand them down until their smoother so the flair meets up better. Very time consuming and annoying though

 

[Ranger850]

Very time consuming and annoying though

that's why mechanic's fees are what they are.

 

[RonD]

Ford OBD2 code list here, most but not all engine codes: https://www.therangerstation.com/tech/obd-ii_trouble_codes/

 

[Tsestak45]

Hey Ranger850, I bought that new O2 sensor and popped it in and it got rid of the P1151 code, for about a week, and then do you know what popped up? A fucking P1152!! I honestly can't take it anymore, I think I'm gonna swear off Rangers and get rid of it. Besides just that code, it idles like shit, has an exhaust I can't get to stay sealed to save my life, and just cost me more and more of the hours of my life every week amd I never get any further ahead with it then I've always been.

 

[RonD]

P1151???

Was P1131-Lean – Bank No. 1

If P1151 now thats Lean – Bank No. 2

You changed BOTH upstream O2 sensor right?
Always need to change both

But yes, send it down the road, doesn't seem to be a good match for you
May be a lemon, rare but possible
Rangers, in general, are just not that much trouble