Okay! It's been over a months journey with fixing this truck, and I'm here to beg for help.
How it started: had an oil change, a while back, on long drive after, check engine light started flashing as I accelrated up hill so I pulled over and in a while it was ok, but couldn't get on the gas too much, or it would cause that flashy light thing.
So fast forward to now, after driving it with an intermittent miss for a while, was driving it to work and the miss became a shudder, and she stopped going over 30-40, and runs extremely rough.
Steady but loud idle.
Replaced all plugs with motocraft plugs and new coils all around. No change.
Finally hooked it up to a computer and got random misfires, now it's saying
P0174 bank 2 too lean,
But it's bank ONE that's the only side misfiring.
Hoping to post my codes here in the hopes that some magician can help me figure out the next step before I start replacing VCRs, phasers, Cats, and sensors.
Stays running if idled, seems to want to die if I try to drive too long.
Strong smell of gas, I don't specifically smell eggs but there are strange smells
Not sure if the oil change is related.
Oil pressure gauge stopped working too, mechanic
Told me it was the wires no biggie.
Ran fine and has had another oil change since. I use synthetic.
Here are the freeze frame computer details:
Frame 1 Mod $00
MIL Status Off
Troub Code P0174
Abslt TPS 24.3%
Eng speed 1665
Baro PRS 71 kpa
Calc Load 100%
MAF Flow 49.99 gr/sec
Out Temp 59
Ign Advance 21.5
ST FTRM1 -12.5% that's NEGATIVE
LT FTRM1 -6.3%
ST FTRM2 39%
LT FTRM2 29.6%
Veh speed 22
ABSLT LOAD 47%
REL FRP 285.19kpa
Fuel Sys 1 closed
Fuel Sys 2 NA
REL TPS 12.9
THROT CMD 15.6%
ABS TPS B 37.2%
ACC POS D 22.7%
ACC POS E 33.3%
ACC POS F 21.5%
Cat temp 11 1229degrees
CAT TEMP21 1229 deg
Evap purge 0.0
Evap vp 0.0
CMD eq ratio .999
ST FTRM 11 -12.5
ST CTRM12 99.2%
ST FTRM21 39%
ST FTRM22 99.2%
Clr dist 0
Clr trps 512
Fuel level 26.6%
So I was thinking Cat converter, vct, cam phaser? But now I'm not sure and I'm hoping someone can please help! Thanks and mahalo!
I'm no expert but you provided lots of good info that should allow someone who knows their stuff to provide you with some good guidance.
I did spot a couple of things worth mentioning. When the CEL flashes, it is to warn that a CAT destroying condition exists. You did right to try to limit that happening. That generally is from a serious overly rich fuel condition that can result in the chemical reaction in the CAT converters generating too much heat and damaging them, or clog the CAT honeycomb with soot.
Although it is seldom that a single code or one freeze frame will solve a problem, Your "freeze frame" data is helpful. There can OFTEN times be more than one problem. One often 'skews' OBDII readings in other areas.
HOWEVER, some interesting things appear in the data you provided that a knowledgeable person can hopefully help you with.
1st. "P0174 Bank 2 too lean" says the PCM is getting lean readings (low voltages) from 02 sensor 1 on bank 2. Since 02 signals, by design, swing from .1 to .9v, the reading (O2S21 .815v) from ONE freeze frame isn't out of line, nor is it TOO meaningful. BUT the reading from bank 2 downstream O2 sensor (O2S22 0.090v) is below the low design reading of .1v, or LEAN (at the instant of the freeze frame) - and sorta confirms the Bank 2 too lean code. So it caught my eye.
HOWEVER. ---MORE IMPORTANT, NOTE the Short Term and Long Term Fuel Trim for Bank 2. (ST FTRM2 = 39%) (LT FTRM2 = 29.6) The PCM is adding 39% plus 29.6% to the pulse width on the four fuel injectors on bank 2 ----- and still gets a lean condition feedback from bank 2 O2 sensors???????? This is not only contrary to Bank 1 fuel trim readings. Both bank 1 readings are understandably negative under your driving conditions when the CEL was set. You may have been letting OFF the gas. Note: 22 mph, 1665 RPM, Mass Air Flow 49.99 [you weren't flooring it], PCM throttle command position 15.6%, and Ignition advance 21.5% all suggests you weren't asking for power. You were just cruising along at 22 mph. There is NO logical reason the PCM should be commanding increased FUEL TRIM on bank 2.
One possibility might be a fuel injector on bank 2 partially plugged or otherwise not delivering fuel properly - causing the PCM to increase injector pulse width on bank 2 - making mixture very rich on three cylinders, and the bad one delivering nothing on one cylinder. You might "inspect" the spark plugs on that bank to see if one is white and chalky (very lean) and others are black with sooty (very rich) Or you could try to clean the fuel injectors. This condition can cause the overly rich cylinders to occasionally misfire, and the overly lean one to intermittently missfire.
(This condition could ALSO be the result of a vacuum leak around bank 2 intake ports - you could spray carb cleaner or starting fluid around the intake manifold and see if it affects idle - or drives O2 signals crazy. But I don't suspect that because the CEL (freeze frame data) will more likely occur at an idel with a vacuum leak - when lean fuel mixture is most critical)
I realize you said the misfires are appearing on bank 1, and there certainly could be a problem there - but I would try to eliminate one thing at a time, and this doesn't look right to me.
On the other bank, just unplug and replug COPs / Injectors and verify electrical connections or use a good electrical spray cleaner on connections - perhaps even unplug / clean and re-plug the connections to the PCM.
But I don't think it's time for CAT Converters, Phasers, VTC's, or other things just yet. It looks like the CAT's are working.
Good Luck. Keep the faith, and keep getting that good analytical data.
I'm with @JWA - what lead to that decision? Hope it wasn't my prior post! I said I'm no expert, and that we should never rush to judgment on one code or freeze frame.
Also, $300.00 for all eight injectors gives me pause.... They must have been reconditioned as new Motorcraft injectors are over $100.00 each. I hope my feeling about this is wrong.
I know it's a pain in the *** to remove spark plugs -just to inspect them- but did you do that looking for ONE lean cylinder that could explain the positive fuel trim on bank 2?
A faulty O2 sensor can produce the same results as a perfectly good one trying to correct for THAT condition. It appears that you have a scan tool. Can you graph your O2 Sensors, or log 02 sensor readings to a file? All four O2 sensors would have been less than $300, and at 117000 mi, they could be getting tired.
Also, if you suspect a "clogged cat", you can remove the upstream o2 sensors and (at the expense of lots of extra noise) go drive the truck. If back pressure is the problem, you can tell the difference.
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