2004 EB 5.4 Stalling when cold P0320 & P0351-P0358 Can't find the short

[tswinehart]

I'm trying to help my grandmother get her 2004 Ford Expedition 5.4 Eddie Bauer back on the road, but every time it's initially running, the engine stutters intermittently. Occasionally it will stall completely. Once the engine has warmed up, 10-20 minutes, the problem vanishes and then the engine runs well until it cools off completely again.

Codes are not consistent, but recently got a P0320 and P0351-P0358 (all cylinders) while it was exhibiting the worst of the symptoms. Heavy engine drop outs and a few full stalls.

I've checked the wire that runs over the A/C line near the battery, and it looks like someones already pinned it up with a zip tie to get it off the A/C line and stop the rub through issue. I saw the post on here about the Junction Box, so we got a rebuilt unit with the beefier internal relay fix, and that hasn't changed things a bit.

I'm feeling somewhat confident that there must be a short in the ignition coil circuit somewhere, or the PCM is going, but it's very weird to me that it cleans up it's act after it's been on for a while. I've hunted all over the harness that I can see well, but haven't found any rubbed through wire insulation or obvious trouble spots. Before I end up ripping the harness apart or replacing the PCM, are there any other know locations to check on the circuit? or some other candidate for the problems we're seeing?

Any help is greatly appreciated.

 

[tswinehart]

Was seeing the most misfires on cylinder 5, and it's easy to get to. Tried a new ignition coil and a new spark plug. No change. Still getting the P0320 and a lot of misfires. Still thinking it's a short or the PCM, but I'm having a very difficult time locating a definitive cause

 

[SafariGoneWrong]

Exact same thing happened to me, that is misfire on #5 only, back in 2012 but it’s an ‘06 3V. It needed spark plugs, all were very worn.

 

[tswinehart]

My uncle thinks the dirty throttle body is a smoking gun? I do see an issue with the PCV valve area being very oily, but it seems like an odd conclusion to link the two issues.

 

[tswinehart]

 

[Hamfisted]

I'm guessing this problem has been going on for a long time ? I can't tell if that was a coolant leak from the hot water hose above it, or a clogged PCV valve allowing all that oil schmeg buildup all over the PCV. Did you pull the vacuum hose off the hot water valve while you were poking around ? I see it's disconnected from the valve. Go to Autozone and get a can of CRC throttle body cleaner and an old toothbrush and clean up the throttle body. Also clean the idle air control valve (spray some cleaner down the IAC inlet pipe. Clean out the PCV valve and make sure it rattles freely (shake it).
You may end up doing a smoke test on the intake system to find any leaks.



Mechanics Smoke Machine on Amazon




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[tswinehart]

No telling how long it's been running rough, but I would guess it's been accumulating crud for a while. It wasn't stalling before though, and that seems to have started out of the blue. After it started stalling some months ago, Grandma wasn't keen to drive it, so it sat for a while too. Maybe the build up was the straw that broke the camels back, or just a brand new issue, I'm not sure. Pretty sure I bumped the vacuum hose off while I was removing the intake pipe. It was reconnected, but the intake pipe is still off right now. Uncle or I will definitely be cleaning the throttle body up while it's apart, and doing something with the PCV mess too before it goes back together.

Smoke test is an interesting idea. Will try to get one if the cleanup procedure doesn't make magic happen.

Thanks!

 

[GaryH]

That throttle body may not be THE problem, but I think it is A problem. Nasty.

 

[tswinehart]

Uncle cleaned up the throttle body while I was at the office today. Left me a new PCV valve, which I installed after cleaning up the nearby hoses a bit. Reinstalled the intake and buttoned it back up. Started and idled smoother but the problem is definitely still there. Heavy misfires while on light or medium throttle. Feels very random, not tied to any particular speed or throttle position. Once, it even stalled when I threw it in reverse and started to backup, only to fire back up again on the first key turn. Once again, all the issues completely disappeared again after the engine bay was thoroughly heat soaked. Much needed maintenance, but I'm super bummed that I don't seem to be getting any closer to the root cause.

We'll get there eventually, for Grandma. I know she loves that car I am starting to hate lol

 

[Hamfisted]

Will your code reader read live data ? Like what are your fuel trims doing ? If you have a laptop and the ForScan app it'll read a bunch of stuff specific to Fords.

ForScan App Download Link




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