cel p0305 p0401

[Mahskeeter]

Good morning,


I will start off by saying, I'm a huge fan of forums to reach out for help. I have done alot of research regarding my cel codes and trying to fix my problem.


I have a 2000 Ford Expedition XLT 5.4. It has 183,000.


Until last week it has run perfect. I decided to get my power washer out and do an engine clean. I know, please bite your tongue. I let it sit a couple hours with the hood up on a nice warmer spring Michigan day. I even moved it around in the driveway, but never went for a drive and really warmed it up.



2 days later I needed to go somewhere and now it has a bad constant miss. It hasn't gotten better despite a couple good warm ups.



I read the engine codes and at first it only kicked up a p0305 (cylinder 5 misfire). Later that day it threw another one p0174(is a LEAN code for cylinder bank 2) At first I changed the coil pack and spark plug, but now I have changed all the spark plug boots and all the plugs. OEM Motorcraft plugs. I was surprised to find a bunch of oil in a couple of plug holes, but the plug itself was firing ad was clean in the cylinder.



After I re-fired the engine I thought it ran well for a sec but quickly began missing again. Constant miss at idle, worse when in gear with brake applied. Miss during acceleration and really shudders when the truck goes into overdrive while maintaining speed.


Last night during the drive I triggered again the p0305 code and now a p0401 (Exhaust Gas Recirculation Malfunction). After researching codes on many forums I didn't really get the feeling that cleaning the egr or throttle body ports, or replacing the DPFE sensor would fix the miss like I have. I should say I have checked all the vacuum lines I can find and have used some electrical spray to try to displace water in any area where there are wires. Like the big plugs for the wiring harness by the firewall on the passenger side.


I have confirmed that that coil pack fir cylinder 5 is firing and have tested the fuel injector. It falls in spec by ohm reading/ can hear clicking while running. The spark plug when pulled is wet.


Any thoughts or direction please?


Thanks Scott

 

[tonydiv]

Part of the problem with the pressure washer is that it's so agressive that it can damage or knock off some vacuum lines. This is probably the reason for your lean code.

 

[Mahskeeter]

I hear you. I had the power washer running to just a little above idle. Any thoughts which vacuum lines I should focus on? I have gone over most of all them that I can find. I have checked the pvc elbow and tubes on both valve covers too.

 

[djewing]

check the rubber boot on coil 5

Hi Mahskeeter,

I know this is old but for the benefit of anyone else who may come across this post i felt i may as well add to it.
The misfire is most likely being caused by a crack in the BOOT of the #5 coil. I have a 2001 expy with a 4.6 and this is a common failure. Napa sells just the boot alone for about $4. I have a couple of old coils I pulled thinking they were the problem. Put new boots on-good as new. Apparently the coils don't usually go bad, but the rubber in the boots decomposes over time. I think your pressure washing just exposed the inevitable boot failure a bit early is all. As for the other codes I'm unsure.

 

[Tigster]

Just for future use, I use my pressure washer. I first hit it with the soap nozzle with a degreaser running through it. Let it sit for awhile, then use a low pressure nozzle to rinse. I have done this with all my cars and never had an issue.