Hi, all. Hoping you can help me out. I have a 1999 E250 with a 4.2L V6 out of (I believe) a 2000 E150--I am assuming they're really no different, at least in this situation. Before you ask a ton of historical questions, I have had this van less than a month, so you know about as much as I do at this point...180k+ on the clock.

I am throwing a P0171. NOT a P0174. System is too lean on bank 1. Bank 2 is fine as far as I know. That seems to eliminate MAF sensor.

Air filter was falling apart. Changed that. Found a questionable connector hose to the oil breather back there. Duct taped it. STFTs were in the negatives thereafter, but the MIL was still on. Removed the duct tape, unsure whether it was helping...

I have searched for and attempted to eliminate vacuum leaks by replacing dried-out hoses. I swapped out my PCV valve with another one I coincidentally had lying around that appeared identical. But I don't know if the one I removed was even right...again, I don't know the van's history too well. For all I know some backyard abortionist did the engine transplant and just threw in odd parts.

--The oil breather connector hose and the PCV valve are due to be changed as soon as I make it to Advance...hopefully tomorrow.

So the help I am asking for is this:

My STFTs fluctuate from 10 to 26% at idle. Pulsing the throttle I got them both under 10, momentarily. Is that because the engine is not warmed up? My LTFT is staying steady at 0.0 -- is this bad? Is this due to the fuel monitor not being ready (disconnected battery to keep dome light off while working with doors open)? What kind of mileage do I need to get that monitor ready?

What should my STFTs look like at idle? At 1500RPMs? 2500RPMs? Is 900+ RPMs too high for idle? (I believe it is.)

Can anyone send me a pic of specifically what the correct PCV valve looks like for this motor? I have seen conflicting pics online, and I know not all PCV valves function the same, so for all I know I'm exacerbating my problem. With the un-reliability of the auto parts stores and the generic parts photos I'm seeing online, is anyone able to provide PCV valve pics and/or educate me on this a bit more? Also, are there multiple PCV valves? The Fram pics shown online would have you believe so...

Also, if I am interpreting all of my live data correctly, it would seem I can rule out oxygen sensors, right?

(I'm not a mechanic, I just play one on TV.)

Thanks for any help in advance, guys.

 

 

Just a quick question have you checked the fuel pressure at the test point? Too low and that could cause your Lean Bank 1 and/or 2 but as you mention its odd to have just the P0171 without the P0174 accompanying it. I'm wondering out loud IF its a fuel preesure issue could there be a restriction in the fuel rail for Bank 1? (This is just me thinking out loud, don't put too much into it.....)

I'd post most of this same info in FTE's Modular Motor forum found here: V8 Modular Motors More than a few very knowledgeable members there who'll give informed answers, point you in the right direction.

Good luck with this!

 

 

Haha, I wasn't seeing any responses and I was becoming discouraged, then......BAM! Everyone is giving me things to check--THANK YOU ALL.

​​​​​​I did not keep my word--still didn't make the auto parts store for the right PCV valve, but I should be able to do that tomorrow...I also will be checking what you're all suggesting, and will keep you posted.

I have NOT checked fuel pressure with a gauge. I am still hoping there's something simple I have overlooked, but I can steal the fuel gauge from work if it comes to that...so far, no "hesitation," no misfire...