The "service engine soon" light came on when we were heading home from a short get away. everything was normal on the way to our favorite TN state Park, camped the week and started home on Friday morning before the weekenders started arriving. The motor started very hard took 4 tries and it idled very rough and the service engine soon light came on. i shut her down checked everything i could think of. everything checked out fine. restarted the rough idle was gone but of course the light stayed on. Came on home and hooked up the OBD11 code reader, and got the PO171 and PO174 codes. lean fuel both banks, which points towards the MAS air meter malfunctioning. i purchased a can of MAS cleaner, cleaned the MAS, reinstalled, cleared the codes. started and drove around a bit everything seem fine. This week we headed out for a quite week, everything was fine until i tried to start after checking in at the CG. again 4 tries before it started and rough idle. again same codes, reset codes, rough idle stopped and we spent a quite week. This morning when i started her up again the rough idle, same codes, but a new one P0300 Random Misfire Detected. again cleared all the codes and drove home. What do i look for with a P0300 code? we have a 2004 F53 with the V10 about 46000 miles.

Check your air filter. We have had problems with the MAS on our Ford chassis. Driving in a hard rain will cause problems, and can damage the MAS. Find a local machanic with truck experience, and talk to him.

Had a similar problem on my 99 v-10.Was a cracked pcv rubber line which created a vacumn leak.

Thanks for the information, i was thinking maybe a vacuum line some where. keep you updated as i research tomorrow.

had not thought of fuel filter, something else to check

2004 V10 rough start & idle | Good Sam Community

jdavidsmi
Explorer
Aug 23, 2015
Still have not been able to remove the 02 sensors and they have been soaking for a while. i spoke to the mechanic at the bus garage where work and he gave me a couple of tricks. special socket, light tapping, heat , i will try them next week.

as for the OBD11 vs the OBD1 code i was going by the sticker on the air cleaned housing. and it said OBD1, but the codes are equal to a OBD11.

all of the coil packs ohm out as OK but i have a couple of spares to carry with me next trip.

i went back over all the vacuum lines, even replaced a couple that just maybe starting to weaking. retighten all the clamps.
Jrork
Explorer
Aug 10, 2015
Okay, I'll offer up what I went thru since it seemed very similar...

Went for a trip and the motorhome (F53 V10) ran great. Shut off to go register at the campground and then went to start it and cranked it and cranked it with no start. Set for a second and did it again and it finally started but idled rough.

Worried about it the whole time camping and when we went to start it and it fired right off. Drove it home and sure enough, it gave me a check engine light. Plugged in my scanner and I had lean miss on both banks like you do.

It became very hit and miss on whether it would start quickly so I checked the fuel pressure and found low fuel pressure (actually, it was marginal but the key thing was that it wouldn't hold pressure).

Changed the fuel filter, changed the pressure regulator with no improvement. I then changed the fuel pump and it's been fantastic ever since. Starts at the touch of the key, idles much smoother and after 2000 mile trip, it performed flawlessly.
rgatijnet1
Explorer III
Aug 09, 2015
jdavidsmi wrote:
I have spent the last 4 hours going over everything, all the vacuum lines checked out, re-cleaned the MAS, checked wiring cleaned the grounds, etc. the motor starts and runs but is still rough no service engine light. i have two 02 sensors and I'm not getting a reading on B2, with my code reader software. by the way this model is OBD1 not OBD2 complicate. still getting a P0300 that comes and goes.

Are you sure??? I'm not there to look at your engine but OBDI codes went out in American vehicles in the late 1990's. Are you sure that you are reading the right OBDII codes for your 2004 engine?
There are spark plug removal issues with your engine so check online before you try replacing any spark plugs for the proper procedure.
2bzy2c
Explorer II
Aug 09, 2015
Thank you for the update
jdavidsmi
Explorer
Aug 09, 2015
Quick update, i have replaced the fuel filter, MAS, and air filter. when i started her up the miss was gone.
i still have the coils and the o2 sensors to do. i was unable to loosen the 02 sensors so i have sprayed them with a penetration fluid, and letting them soak a while. i will start checking ohms on each coil tomorrow. thinking it may only break down when hot.
2bzy2c
Explorer II
Aug 07, 2015
Any updates?
427435
Explorer
Aug 04, 2015
allbrandauto wrote:
I am sure you have a bad coil a po300 random miss fire on a ford takes awile to throw a hard code like a po302 would be cyl. number 2 if you can find somebody that has a scanner you can go into power contribution and see which cyl. it is

If only a bad coil, why wouldn't it start?

The V10 starts fine and runs surprisingly well on 9 cylinders.
tderonne
Explorer
Aug 03, 2015
jdavidsmi wrote:
I have two 02 sensors and I'm not getting a reading on B2, with my code reader software.

Need to figure this out....

Is it stuck rich? Or lean? What are the short and long term fuel trims doing in that bank? A dead hole might cause this, lots of oxygen flooding that bank's O2 sensor. Could be quite a few things, but no O2 reading in one bank only is a big clue. Could rule out things that affect both banks too.
allbrandauto
Explorer
Aug 03, 2015
I am sure you have a bad coil a po300 random miss fire on a ford takes awile to throw a hard code like a po302 would be cyl. number 2 if you can find somebody that has a scanner you can go into power contribution and see which cyl. it is
rkentzel
Explorer
Aug 03, 2015
May be idle air control

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2004 V10 rough start & idle

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