Hello everyone, I am troubleshooting a problem with my F250 and am looking for some input. It's an 03 F250 CrewCab 4x4, AT, V10 with 143k and no mods.

I did a bunch of reading but didn't find anything that matches my combined issues. I've had the truck for about 4 years without any problems.

A month or so ago the ABS light would randomly come on and go off, then I noticed a slight slip that I thought was coming from the rear axle and developed a slight miss at idle randomly. Researched and replaced the rear axle VSS Sensor, no change. More research, replaced the axle gear oil & additive, no change. Then last weekend, towing a loaded trailer about 10 miles with no problems, stopped off-loaded the trailer, went to leave with the empty trailer and the truck shut off. Cranked back up, idled rough, put in gear shut off, OD light flashing and engine light on.

Had it towed home, got code P0720 (OSS), replaced sensor, no metal shavings on sensor, cleared code, cranked up, idled rough and no code until I put it in drive, then shut off, cranked up, OD Light & Code came back.

I've done a lot of reading and sounds like it could be a COP? It's pretty clean under the hood, cowl seal doesn't leak water (yet), so I know the coils aren't water logged.

Any advice will be greatly appreciated as I really don't want to take it the dealer unless absolutely necessary.

Sorry for the long post, and thanks in advance.

 

Check all the grounds... and check your battery and alternator. It wouldn't be the first time someone got an OSS code and the battery was near death

 

Thanks for the reply. Checked alternator, and looked at the major grounds and re-grounded most of them. Battery is good. No change.

While I was messing with stuff, I decided to look at the MAF. Took it out and it's clean, surprisingly clean, so while the MAF was off I put the filter back on and hit the key, and other than a low/high idle - no skip. Put it in gear, no skip, did throw a P0113 code (IAT), power braked the truck, no skip, no tranny code.

Re-connected the MAF put it back together, cranked it up and no idle skip, but does skip rapidly above 1500 RPM's in gear. Took the MAF back out, everything seems good except the P0113 and high/low idle.

Do you think this could be the issue or am I masking the problem by giving it a bigger problem?

I dislike the idea of a $100.00 MAF if I'm headed in the wrong direction.

Replies appreciated.
Thanks again.

 

REmoving the MAF from the equation is masking something else, I'd bet.

 

I went ahead and sent it to the dealer... They called and said it was a bad #2 Coil and all of the spark plugs were shot.. He told me it usually takes 2 coils to make it act like it was, but being that the plugs were bad too, that was it.

I had them do the diagnostic (obviously), coil, plugs and oil change (because it was due anyways) and it came to $838.18.. News not as bad as I expected, price I guess is good, either way I'll have my truck back tomorrow and I hope it stays good.

In 4 years and 75k miles, counting this time, I have spent about 2k in mechanical failed parts - so I guess I can't complain too much..


I'll pick it up tomorrow and report back on how it goes.. Thanks for the help.

 

So far I have put about 280 miles on it and it seems to be doing great. I think it will be good for a while again. Thanks again for listening and helping.

 

Thanks for your following up------adds to the knowledge base of problems experienced and their eventual cure or fix.

Were the plugs original with 143K miles on them? If so that's impressive only because I'd never think any spark plug would last that long!

 

The factory plugs were changed out around 80k..

Fuel mileage also improved equal to about a 30 additional miles per tank.

 

Mine were original when I got the truck at 142,000 but they were way beyond needing replaced. Average gap on them was about .080 with some higher! Needless to say, my MPG jumped dramatically when I changed them.

 

In the near future I hope to acquire a new-to-me E 350 with the V10--when I do the first thing that'll be done is new plugs ASAP. Naturally there'll be other inspection and repair items but this would be the most time intensive and so easily fouled up by unsuspect or uncaring "mechanics" its just not something I'll trust to anyone unknown to me.

Stil with 142K miles on plugs I'm stunned it even started! WOW!!

 

142K plugs definitely = wow...