I am looking for troubleshooting suggestions.
My truck check engine light came on about a week ago.
I connected my scanner to it and it showed lean condition in bank 1.
So i started trying to determine if it was a vacuum leak or a sensor issue. With tool connected i sprayed ether (maybe not the best idea but all i could think of at the time) into the vaccum line to see if the O2 sensors would increase. They both responded and went to over 800mV.
I then monitored the LRTrim 1 & 2. I read that they should range between -10 to +10 under standard conditions. They were around 12 at idle and when i rev'd the engine they would go as low as about 6 and back up to about 20 before balancing at around 12 again.
I replaced the evap return tube that connects from the rear of the throttle body to the green fitting because it was very disintegrated. Cant find any other potential vacuum leaks.
Then this morning when i started it, it rained all night, the truck was shaking badly as if it had dropped a coil pack. I have replaced coil pack 4 twice since i have owned the truck.
When i checked the codes it says misfire in cylinder 3, Bank 1 & bank 2 lean conditions.
LRTrim1&2 were both at 23-25. O2 sensors bounced around but spent allot of time between 600 and almost 900.
I started looking around the motor for a vacuum leak again but still cant seem to find one. When i turned the truck off the EGR vacuum regulator solenoid was making all kinds of racket and continued to for probably 30sec. I tried starting and stoping the engine again and it made the same noises. I have never noticed it doing that before.

A little more background information. My AC system works fine but there is a problem with the valves. If i have it on MaxAC is the only way cold air comes out. And if i accelerate too hard i hear a thump and it starts blowing hot air.
Similarly in the winter when it is on heat it will start out blowing cold air. If i take off from a stop i hear a thump and the heater starts working.
The heater puts out great and the AC is cold as ice.
Could this valve be vacuum actuated and this possibly be my problem?

So where do i start?

• Replace EGV vacuum solenoid?
• Replace Coil Pack on cylinder 3?
• Search for leaks in Intake manifold gasket?
• Take dask apart looking for vacuum lines leading to AC controls?

Any help is much appreciated.
Thanks

 

Check the pvc elbow on the back of the intake for leaks, if you haven't already.

 

Replace EGV vacuum solenoid?
Not sure what that is..Explain.

Replace Coil Pack on cylinder 3?
5.4L's don't use coil packs.

Search for leaks in Intake manifold gasket?
You can if you want..use propane though.

Take dask apart looking for vacuum lines leading to AC controls?
You got me on that one as well.

 

I replaced the coil. And I guess u call it coil over plug instead of coil pack. Fixed the misfire in cylinder 3. I also replaced the EGR Vacuum solenoid. Which that is its actual name. I also replaced the boot on the throttle body where one of the main vacuum lines attach.
Still have lean condition in both banks. LFTrim 1&2 are now at 25. If I get on it hard it will drop down to single digits.
The pcv line doesn't appear to be leakkng.
I was asking about if there were vacuum lines behind the dash for the ac controls. Since I have vacuum leak and ac problems.

 

Learning, cool. Well close enough anyway. Yes there is a EGR "System" Vacuum Solenoid, but the actual part is called the EVR (EGR or Exhaust Vacuum Regulator. Which is yes, a solenoid. The parts actual abbreviation is EVR, -so you know. The EGR is just a saucer looking valve that open and closes via PCM, -EVR then diaphragm (EGR). Just to be clear.

Anyway, the EGR system has nothing to do with your problems.
__________________________________________________ ____________

Coils -

Yea, -it's just a coil. Your close though. Ford abbreviates it,- COP CoilOnPlug.

You had a misfiring coil that is now fixed correct? That wouldn't net you lean codes, you have an unmetered air leak before both banks. We need some numbers here. Get rid of that scanner if it can't produce DTC's. Don't really care about the other info posted as it means nothing to me and probably for most on this site. You say it's lean, but I don't see any DTC's posted up. I'm with JCR 56 so far here.

So use a scanner that will spit out EXACT DTC's for yuh and we can probably lead you in the correct direction.

 

Its does spit codes. And if u look look at the ford codes. There is only 1 that says lean bank. So u can't confuse them. From memory its something like p1701 and p1704

 

I checked the line coming from the pcv valve to the back of the intake. No leaks.

 

Is that right ?... Yea Okay lol

Oh hey, good luck.

 

P0171 & P0174
Read them on the way to work.

And btw a smart-a$$ response about my scanner deserves a smart-a$$ response in return. if you cant handle it dont dish it.
There really is only one single code that even has the word lean in it. I just checked. And that is this code.

Next on my agenda will be further looking into the MAF sensor. Fuel pressures. And propane checking the intake manifold gasket for leaks.

thanks again

 

No problem, yea I was just having trouble with the smart part. Just post the DTC's you'll do better at receiving help. Now that you finally got past that, just post them in the search feature on this site. That question is asked about once a week.

 

I have searched and read forums. But almost everything i read i have eliminated as being the cause. I am going to clean the MAF sensor again. And monitor the MAF voltage throughout the RPM range and see if I get reasonable values. if not im going to replace it. IF i can reasonable conclude it is performing as expected then i am going to propane test the intake manifold for leaks. If i dont find anything there then im really starting to run thin on ideas. I guess the next step will be to test fuel pressure.

Would it be reasonable to consider an exhaust leak could cause these symptoms? I haven't looked into that any more since spraying ether or carb cleaner into the throttle body causes the O2 sensors to jump up to around 900mV.
One other question i do have though is that both the front O2 sensors dont seem to jump up at the same time. More like one jumps up then the other. And the first one goes back down about the time the second one goes high. It all happens within about 2 seconds. But that is what i am observing.

 

The MAF voltage is around .9v at idle. About 1.39v @ 1500 and 1.75 @ 2500. Seems reasonable to me. Guess I need to propane check the intake manifold gasket.

 

97 F150 5.4L Triton P0701 P0704 Lean Condition: http://youtu.be/uZXhP5yn0Po

Took a video of the data. The engine almost died three times on my way home from work. At higher rpms it does fine. Takes a while to idle down when you release the accelerator. Then it idles fine. Then all of a sudden the rpms will drop lftrims go to 0 and it almost dies. It will stay at that condition until u tap the accelerator. It then repeats the same process.

 

You have a big vacuum leak. What are the exact codes? P0174 & Po171? ruff running? Vacuum leak.

 

Yes that's the codes