Hello Everyone,
I am new here but have been scouring boards for awhile. I'll try to make this as succinct as possible.
I have an 01 f-150 with a 4.2L V6. I recently took it into the shop to have the exhaust pipe redone and have the engine light looked into. They claimed the gasket on the intake manifold was causing the "lean on bank 1" and "misfire on 3" error codes. Easy fix, I took it home and did it myself, rather than the $600 he wanted for only the upper gaskets. I did both upper and lowers and it seemed there was some minor leaking.

After getting it together I noticed it running a bit rougher, especially when in gear, but not so bad at idle. Unfortunately, I had to drive it during this time and had to wait a couple weeks to get a chance to look at it due to work. In this time, of course it got worse and shakes like crazy. I went through and checked all of the lines again to be sure everything was where it was supposed to be. After that time the only code showing was "lean on bank 1." After inspection I found the pcv valve just hanging out. So, I changed the oil, put in some seafoam in case any moisture got in, and changed to a new pcv valve. Lines seem ok, no vaccuum leaks on the lines that I could tell. I also changed the plugs and wires while I was there.

Started up and still not working at all. No change. It still runs with a horrendous shake, more so in gear than at idle, has very little power and feels like it is having troubles getting through the gears. When I took it out for a test drive, I even got a blinking engine light, which according to the manual is a "catalytic damaging misfire."

Any thoughts? It still seems as if there could be a vaccuum leak but I haven't noticed anything visible when sprayed. I thought about chaning out the coil but that seems like it would have been more specific than just lean on bank 1. I am going to try to clean the MAF today since that is inexpensive, and I suppose there is the O2 sensor on that side, but from the looks of it, it's not going to come out easily, which would mean replacing that section of exhaust too most likely.....

So again....any thoughts?!

 

You sure your running on all 6 cylinders?? Also wonder if the cats could have went out on you.

 

I'm not trying to doubt your ability or anything, but are you absolutely sure you have the wires set right for the firing order? I've seen many times people are frustrated and they over looked the simplest of items.

firewall
36
25
14
front

 

Also check all the connectors to the injectors. I know this doesn't really make sense, but somehow one of the harness side tabs on my #3 injector broke off while still connected, causing my truck to misfire only when unde slow acceleration. Idling and high rpm were fine.

Just my thoughts.

Hope you get it figured out, and welcome to the site btw!

 

Save your money on the O2 sensor. It's reporting the lean not causing it.

I agree with Chris, check the firing order, I think there are 2 different orders for the v-6's.

Also dirtyd 88 called it, check and double check all the electrical connections.

Does it have any codes? That would help.

 

Thanks for the replies everyone. No worriesChris, I know what its like to pass over the easy stuff too and try to communicate that to people.
I've checked the firing order a few times via my book and various sources just to be sure. Everything there is in order sadly, or fortunately depending on how we look at it. The V8 is the engine with two different patterns for this year.

I drove it up the block and back to see if I could get any new codes.

P0171 System Adaptive Fuel too Lean (bank 1)
P0303 Cylinder no. 3 misfire detected
P0304 Cylinder no. 4 misfire detected.

My brother in law mailed his OBDII sensor to me today to check the codes. When I get off work I'm going to run the system test on it and see what I can record and put on the comp.

 

Hmm, I see that you changed the plugs and wires, but what about the coil pack? Mine went around 95K-100K. I had a slew of other issues around that mile stone, many of which you have already replaced (PCV elbow, upper & lower intake gaskets, new plenum isolator bolts). But when I did my plugs and wires, I also did the coil pack.

 

King, I'm already worried my catys have gone for sure.

I'm thinking about my coil pack and the only reason I haven't changed it yet is due to the cost. Thankfully my mom works commericial at autozone so the parts are usually 40% off or so.
According to my manual the valves are as you listed but the coil pack is

firewall
3 4
2 6
1 5

 

Have you checked the MAF? your issue sounds similar to one I had, bad MAF was the culprit.

This was several years ago, but I seem to remember multiple cylinder misfire codes, o2 (or Cat?) out of range (?) Lean and Rich codes... it was all over the map.

 

Good thought Jerry. I went that way first, if I didn't mention it originally. I cleaned the MAF and when I took it into the shop they claimed the readings on it were fine. I've looked into so many different things I'm sure I'm forgetting to list everything.

I'm going to go out yet again to check my wires since at this point, why not check everything again, lol. Granted at this point, I may not be able to count in the correct order anymore.

 

OK, I ran outside last night while the wife had the kids for a few seconds and got a quick reading off the system. Bear in mind I checked it immediately after starting it up and in 20 odd degree temp.
My codes changed. While I only had p0171 before, system too lean on bank 1 and p0303 cylinder 3 misfire, last night they changed.

New Readings:
P0174 Bank 2 too lean
p0303 misfire in 3
p0304 midfire in 4

and from the data at idle:
abslt tps % 18.8
eng speed rpm 963
calc load % 19.6
maf flow g/sec 8.81 or 1.165 lb/minute
coolant F 96
IAT F 26
IGN advance 17.5
st ftrm1 % 2.3
lt ftrm1 % 3.1
st ftrm2 % 2.3
lt ftrm2 % 28.1
veh speed mph 0
fuel sys 1 open
fuels sys 2 n/a
o2s11 V 0.040
st ftrm11 % 2.3
o2s12 V 0.635
o2s21 v 0.040
st ftrm21 % 2.3
o2s22 V 0.130
obd2 stat CA

My wife has off work today so I'm goign to try to at least clean up the MAF again. If I can make it to AutoZone I may go grab a new coil pack. Injectors keeps popping into my head since they were so stubborn reinstall last time....

 

I'm still betting coil pack. Good luck, hope you get er' fixed once and for all.

 

Sorry if I missed it (speed reading) but did you check your spark plugs?

 

You better brush up on your speed reading.

 

I bet it's an intake manifold gasket.