On the 01 3.0 I just bought it has 4 codes. P0174, 304,305, 306...any ideas?

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No opinions, just fact. You have misfires on 4, 5 and 6. That bank is also running leaner than your computer likes to correct for.

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Here is Fords opinion:

P0174 - System to Lean (Bank 2) The Adaptive Fuel Strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit. See Possible Causes for DTC P0171. See Diagnostic Aides for DTC P0171

(Possible Causes for DTC P0171 For lean and rich DTCs
Fuel system
Excessive fuel pressure.
Leaking/contaminated fuel injectors.
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel.
Vapor recovery system.
Induction system:
Air leaks after the MAF.
Vacuum Leaks.
PCV system.
Improperly seated engine oil dipstick.
EGR system:
Leaking gasket.
Stuck EGR valve.
Leaking diaphragm or EVR.
Base Engine:
Oil overfill.
Cam timing.
Cylinder compression.
Exhaust leaks before or near the HO2Ss.

P0301 through P0310 - Misfire Detection Monitor The misfire detection monitor is designed to monitor engine misfire and identify the specific cylinder in which the misfire has occurred. Misfire is defined as lack of combustion in a cylinder due to absence of spark, poor fuel metering, poor compression, or any other cause. Ignition system
Fuel injectors
Running out of fuel
EVAP canister purge valve
Fuel pressure
Evaporative emission system
Base engine
The MIL will blink once per second when a misfire is detected severe enough to cause catalyst damage. If the MIL is on steady state, due to a misfire, this will indicate the threshold for emissions was exceeded and cause the vehicle to fail an inspection and maintenance tailpipe test.

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'20 Ranger Lariat FX4 Oxford White

Yeah just what I said...

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Looking for a professional retrofitter to add HIDs or LEDs to your Ranger? PM me if your looking to have work done, and have cash to spend.

Thanks for the info. When I bought the truck I figured a burnt valve but I didn't figure 3 cylinders were missing so it kinda makes me rethink my initial diagnosis. Seems odd that it would burn 3 valves on the same head(not like it couldn't happen, just unusual) The PO gutted the cats because he thought they were the problem($%#@) He also installed a new coil pack, plugs, wires, and cat back exhaust.I haven't had much time to check things out but did notice a new pcv valve so someone must have been on the vacumn diagnosis track.... I should have more time tommorrow to check it out.

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22 and counting...

My P0171 diagnosis was a vacuum leak. A hose near the air intake was spliced. I had the egr code also.

Update!

Well sometimes you just get lucky....lol

I pulled the upper intake to look for problems and I found 1 fuel injector without the plug even in place and another that had the rubber seal blocking the connection. I bolted the intake back together and took it for a spin and guess what ....it runs good...no miss

Its not missing but if you rev it past 3000 it acts like something is cutting out and causeing a miss but when you drive it its smooth way past 3000 rpms. Its not idleing perfectly smooth but I was thinking maybe the empty convertors could be causing it. I'll swap out the convertors and see what happens...

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I have this exact odd problem with my 4.0L Ranger, runs great with high rpms, however rev'ing at 3,000 rpms it misses and feel like a washing machine. Did you ever find the cure for your problem, which seems like the same for mine. Thank you

I don't know what year it started but with the auto's if you have it in Neutral or Park their is a limiter that kicks in at 3000RPM. The only way to get rid of it is with a tuner.

Thank you for the answer, that would explain a lot.

yep...what he said...lol

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