My 2002 F250 V10, which I've owned about 90 days, just started running rough, it sounds like it is missing both at idle and at higher RPM's. It seems to misfire for 2-3 seconds, then be ok for 2-3 seconds, and repeat. I haven't owned it long enough to know much about how to fix it, don't have a service manual yet, etc. It hasn't given me any codes yet. I tried driving it a few miles to see if it would clear up, but it hasn't. I was getting ready to go out of town for memorial day, so I parked it and have been driving assorted other vehicle. Should I keep driving it to see if I get a service light? Or just start the routine with replacing coil packs one by one, then spark plugs? I'm afraid to take it to a mechanic, I fix all my own junk 99% of the time.

Also, if it isn't ignition and its fuel related, how hard is it to clean injectors? I need to de-pressurize the fuel rails somehow first, correct?

 

How many Miles?
Have you tried getting a scanner that reads misfires ? cheap scanners don't !
This would point you to the cylinders and cop's that are failing.If thats your problem.
maybe you should should get one that does ,they are great to have.
Misfires won't set a code until they reach a preset threshold in the pcm (quite high).
could be months.
You could pull the plugs and look to see any difference in the read of the plugs.
Also take a look at the cop for carbon tracking or cracks in the boots.
You could have a fuel delivey problem
Fuel pump
injectors
filter
or injector wiring

You can depressure the fuel by pulling the fuel pump fuse or release it on the rail

Rich

 

I have 47,000 miles on the truck.

I have been holding off getting a good scanner until I got the F250, wanted to make sure whatever I got would be good for all my vehicles, I'm aware of the differences in capabilities, I don't mind spending $$ on a good one if I am sure its what I need. But I haven't researched enough to know whether I need the $300 one or the $3000 one. What scanner do you recommend for fords, preferably a "stand alone" one and not PC or PDA based?

I only drive the truck normally maybe 150 miles a week, if that. A tank of gas lasts me 2-3 weeks unless work sends me somewhere out of town. Since it started missing, I only drove it maybe 5 miles. So if it would take months to code for most, it might take me years.

 

You didn't happen to wash the engine did you?

Otherwise, I'll go with what Rich said and begin the troubleshooting along those lines.

BTW - I haven't got a clue what scanner might be best - I have a good tech at our local Ford dealership that does all that.

 

I have an autoxray scanner.they have a website chk them out!
If you have a autozone, they used to scan for free.
You could just run some injector cleaner through it and change the fuel filter for starters.

Rich

 

Big Orn, I washed my engine and the next day it ran rough, but it seems to have dried out now. Is there a common problem with engine washing and V10's that I should be aware of?

 

Moisture under the COPS. Cracked boots on the COPS. Either way there is most likely still moisture in there causing you problems. Use compressed air to blow them out really good and you should be fine. Might even have to pull them and blow them out. I used to wash and degrease my 460's like every weekend but havent touched my V10, heard too many stories.

 

You're lucky. Most of the time the water will get past the coil sealing flange and into the plug cavity where it vaporizes and gets into all the nooks and crannies. What happens next is that the very poor rubber that the OEM boots are made of begins to deteriorate and allows the sparks to jump into the plug cavity. You begin to notice "spark marks" on the boots. After that it's just a matter of time before a COP begins to fail - the engine misfires, but not enough to throw a code, and you pull your hair out trying to figure out just which COP it is.

Some folks here can wash their engine with no problems - some, however, can't even hit a mud puddle and get by with it.

 

I had the same problem with my 02 5.4 F250, Changed the IAC valve, plugs, checked resistance on all the coils, checked fuel delivery pressure, changed air and fuel filters, no codes with my cheap scanner, all to no avail. Never had washed the motor either. Few days later it started running fine again, this happened around 60k miles, the truck now has 80k and still runs fine. My dealer assures me if it ever does it again to bring in and they can hook their scanner to it and drive it and he can tell me what the problem is for $65 which seems fair enough. Of course it won't do it again until I am towing a trailer hundreds of miles from home,,glmf

 

I would have to hook-up to a trailer, load it to the max, and take it to the dealer. I could never make the engine in my truck duplicate its symptoms until I did it.

 

Big Orn, read that post, it says, trailer loaded and hundreds of mile from home!!!! Have had the trailer loaded to the max many times and the truck runs fine. Just haven't had it hundreds of miles from a dealer yet! Funny how those things work huh?!!! And my post above should have read: changed air and fuel filters,

 

Believe me...I know what you mean...

I'd be down in the riverbottoms with a frontend loader and all the attachments on my trailer, in 4WD, low range, creeping up a hill scarred in deep ruts, trying to idle along and get that nagging little PHRUMP!~~~PRUMP~~~PHGOO~~~PHOO-PHOO.

...and wondering what did I do to Ford for them to give me such an elusive problem...

 

I haven't washed my engine, but maybe the previous owner did when getting ready to sell it. I haven't ruled out bad gas either, but I fuel all three of my vehicles from the same stations and they don't have any issues. Any risks with driving it some more to see if it will clear up? I know persistant misfire can lead to carbon deposits, but I'm wondering if 20 miles on the highway might be a good idea before I commit to troubleshooting and spending $$$.

 

It depends on how bad the misfire is, imo. I drove my truck about 500 miles before deciding I couldn't locate the miss - that was about 50K miles ago and no problems.

When it starts to misfire, is it a dead miss - like really torquing the engine - or is it just sort of a stutter?

 

More of a stutter. Watching the engine, it doesn't make it shake that much, but if the passenger seat is empty, I can see the seatback shake back and forth a couple of inches, seems like the resonance travels best through the transmission mount. The tach twitches a bit, I can feel and hear it in the cabin, and I can really hear it standing at the back and listening at the exhaust, I have Borla dual cat-back, so the exhaust at idle is louder than stock.