First, I'm Jim and I'm new here. Seems like a great place with some real knowledge.

Now, I bought this 2000 Explorer, EB, 5.0 AWD for $1400. It was shooting codes like mad... 27 of them. Without boring anyone to death, the important ones were Misfire 5, EGR low, IAT low, and O2, bank 2 positions 1 and 2.

So, I put two new downstream O2 sensors in (because I forgot about the position 1 code), I pout a coil on, new plugs and wires, new DPFE.

I still coded for bank2 p1 so I bought and installed an upstream O2 on bank 2... except I put it on bank 1 instead. When the code came back, I realized my error and took the one I removed and place it in B2 P1.

Everything was great for 1 day, the I got a 0174 for Lean condition on bank 2. I've cleaned the MAF and metered it (backprobed while operating) and it checks out fine. I checked every possible line for a vaccuum leak, including the intake manifold gaskets.

I'm at a loss. I have this stupid code and it comes with a rough condition between 1100 and 1600 RPM.

Could it be the O2 sensor? I would think not as I'm not getting a code for it. If it were upstream of the exhaust, wouldn't I code for Bank 1 as well?

Any help would be great. I've been reading about this condition for a while and have seen no resolutions.

 

Welcome to the forum,

Check/replace the PCV, also check rubber elbow on PCV

 

Replaced the ever-so-hard to find PCV. Code has been cleared, all monitors show ready, no code yet. Unfortunately, that 1100 - 1600 rpm rough condition prevails. Any suggestions on that would be great. I'll update on the code tomorrow

 

Run it for a cple of days and see if a miss fire code comes up, then we will chase that..

Pour some Tecron injector cleaner in the gas tank..

Take it for a good run (High RPM, 2nd gear), get it real warm and blow the carbon out.... Philip

 

If the rough condition showed up after the tune up as it sounds like it might have, I'd suggest you recheck all your plug wires to make sure they are solidly seated on the plugs and coil towers. Unfortunately I've been reading about a surprisingly large number of folks finding cracked spark plugs recently. I frequent a few Ford forums so many of the plugs being used are Autolites. It could be due to overtightening, improper use of socket wrenches, or possibly a manufacturing defect. Or it might just be coincidence, but something to consider.

-Rod

 

That is exactly what went through my mind, hence looking for miss fire... pending

 

Well, the code came back. I did plugs a couple of weeks ago and the coil last week and no misfire since. As I pay close attention to this engine, it really runs like crap at idle too. I only notice it under load and lower RPM. It gets bad enough to make your teeth rattle. I'm really at a loss, especially with no other codes. I'm praying for a vacuum leak to show up and make my day but I'm afraid that with only the 0174 (and no sign of the 0171) that I might be pulling injectors, which for the record might make me cry. I'm really running out of ideas.

It occurs to me that I should give a little more about the prior condition. Before I changed the plugs, I was missfiring #5. I pulled the plugs and the gap was wide enough to swing a dead cat through. All new motorcraft plugs. I was coding for insufficient EGR and tested the valve with vacuum and it worked fine. I went for the DPFE, knowing those like to go bad. The coil ended up solving the #5 problem and the IAT code just never came back, which I thought a little suspicious. Now, it's just this damned lean condition on bank 2. I even swapped O2 sensors to make sure it wasn't an O2 problem but the code stayed the same.

I know it's either 1) Too much air, 2)too little fuel, or 3) a bad piece of info from another sensor.... which is bad but not throwing a code.

 

Do you have coil and wire or COPS?
Have you performed a fuel pressure test?
follow my previous directions and eliminate a stuttering injector.

 

Coil & wire.

I've not done a pressure test.

I bow to your prediction... I now show p0300 and p0174 pending. I've run the techron, or it is running now. Could this be a dirty injector misfire? I ran it for about 45 minutes taking the kid to school. I kept it in second and ran between 35 and 45 MPH, 2000 - 3200 RPM.

 

P300 is a random misfire, I am hoping for a specific # to settle in (P305-P308).
Have you confirmed that all wires are on their respective plugs and secure?
What did you gap the plugs at and what ones did you install?

 

I've confirmed the wire connections and I installed Motorcraft plugs. They were supposed to be pre-gapped. I did just get a 0305 pending, same as before.

 

For future reference, do not believe the pregap story, however they are probably close enough.
OK, so same pot, either we have a poor firing plug, manifold leak or a sticky injector.

My inclination would be to run extra injector cleaner through a couple of tanks and see what happens.
Next I would pull the plug and chase the thread (Thread chaser-Not a thread cutter) in the plug hole, check the plug for colour and fire condition.
Lastly I would suspect a leaky lower intake manifold gasket or valve cover gasket.

EDIT: just re-read your first post, confirm you have an old O2 on bank 2/1... do you have access to a scanner capable of live data??

Barring that, and I know it is a pain, could you switch the upstream O2's and see if the code follows...(note, I am not a fan of just changing parts and throwing $$$$ at a problem, diagnostics is my game)

 

Already switched the upstreams and the code stayed. I can only read codes after they happen, no live information. I just pulled #5 and checked it for gap, .055. I cleaned the thread space and rplaced it. It was carrying a light pink haze on one side. Otherwise, it looked good.

Would it pay to run Sea Foam through the top end?

 

Not having access to sea Foam in Canada, I have not had the opportunity to use/test it.
I am not sure it will have any desired affect, but cannot hurt if you wish to proceed in that direction.
Confirm, When you switched the upstream O2's, you did clear the codes and it returned on bank 2.
At this juncture I am leaning towards a leaky lower manifold "O" ring (Gasket), and if here would apply smoke to the intake @2psi.(upper would create the P0171&0174, common plenum).
Did you check the valve cover on bank 2 for leaks, torque the bolts (gently).

However keep your chin up...

 

correct on the O2 swap; the code returns on B2 after a reset.

I'll have to figure out how to test for manifold leaks. I don't have a smoke machine and have never had luck testing with propane.

I might run the Sea Foam just as a helpful measure. It can't hurt.

I haven't checked the valve cover... mostly because there is no oil leakage. It can't hurt to snug the bolts up a bit.