I have a 2000 f-250 super duty w/v-10, bought new 10/99. truck and motor have 125k on them. All maintenace has been done on a regular basis. While driving on the interstate the other day at about 70mph, let off the gas to exit and the truck shuddered. Then it started running rough and sounded like the exhaust was plugged up. All guages read normal, and tach was reading fine at idle, but truck was vibrating badly at idle. took to Ford dealer, was told I needed new plugs, and should have all 10 coil over plug caps replaced. I did not want to pay them the $850 they wanted, so I replaced plugs first, then took to local auto store to have codes read. They showed cyl's 5 and 10 miss firing. Replaced those two caps and reread, still showing cyl 10 not firing. Took to another Ford dealer and was told low Cyl pressure on cyl 10 and could be possible bad valves. The motor idles very rough and has an exhaust sound like it is plugged up, but no metal sounds. Once motor is revved up past 1500 rpm, smooths out slightly, but exhaust sounds same. While driving it has slightly less power than normal. Any suggestions would help, any other info needed will be happy to supply, Thanks.

 

Which pressure test did they do? Compression or leak down?

A leak down is better (at least to confirm poor valve sealing) simply because it is easier to determine when the pressure is being lost. If it is a worn valve, then the tester should be able to hear the air escaping past the valve.

By their "could be possible bad valves" statement, it makes me think that they didn't do a leak down test. They probably ate lunch on your hood while the new guy revved up the engine a couple times. Then the overpaid, overweight, under-showered, never-gets-his-hands-dirty Service MGR came over with half a tuna sandwich dangling out of his mouth and Fritos in his moustache and said "Juf say nufner fen cylnder ith bad".

Go to an independant shop. But I would try to look at the wiring going to #10's COP and see if it is frayed or even disconnected first, though. I would also swap it with a known good COP. Say #8's.

 

BTW, Welcome to FTE!






This is post 9500 for me.

 

I agree with Monsta. Remove the suspected bad cylinder COP and replace it with #1 or #6 (easy up front removal). See if the systems problem moves to that cylinder. If it does, then you could have another bad COP.

Please post back with any results...and more FTE folks will be happy to help.


biz

_______________________________
2003 F250 SD SC 142" XLT FX4 V10 Auto 4x4 3.73s

 

Monsta, you crack me up. 9500 posts. Yee HAH!

dccowgirl, WELCOME to FTE!

What I don't think is right is that it suddenly started doing this. That doesn't point to a "bad valve". A bad valve gets bad over time, it doesn't just start doing it.

And more coincidentally, #5 was misfiring too.

I'd have a good mechanic check that both the injector and the COP are getting signals. I'd also check for vacuum leaks, stuck open EGR, plenty of other things.

If the dealer didn't charge you to check the compression in all 10 cylinders, or even that one, they NEVER touched it. They'd charge you for the diagnosis, unless you worked that out before hand.

Something sounds fishy...

More people will chime in on this, so wait a day before doing anything.

To me, something's fishy...

 

That dealer doesnt seem to be stearing you in the right direction. I would have a good mechanic look at it and there are a number of diiferent things that should be checked before major engine work is done.

That cyl needs to be checked that it is getting spark and fuel. Id bet money its a bad COP, or fraid wiring to the COP.

 

did they do a compression test. and did they tell you how much loose it had.
i'm betting a bad cop unit or a pluged injector before any thing else.
when i worked first move was to code test. to find the cylinder miss fireing then do a compression test and a leak down to check the rings. on all cylinders . all the plugs most be out for a proper test. there are two ways to test compression wet and dry. first is dry if you have a low reading add a few shots of motor oil and retest if the compression comes up its bad rings then you do a leakdown to check the amount of loose . then with a ohm meter check the injector for a open circuit, same with a cop unit you can check the circuits even thou it has more then 2 wires read the manual. the newer lead free gas motors go a lot longer before burning a valve or seat but worn valve guides can start causeing valve problems still it doubtfull in my mind

edit
don't go back to that dealer they smelled selling you a motor job due to your miles, as you said suddenly it's most likely electric or injector .

 

Those notes are for me. Let's me see my "milestones".

 

Thanks.

Reason I said #8 is that it is right next to #10.

 

Uh, you thinkin' Chevy? The one right next to 10 is 9

 

Really? I thought the even number cylinders were on one side and the odd #'s on the other...

 

1-5 on pass side, 6-10 dr. side.

 

ken
have you have to many myties tonight? you for one know better .
and next spring we are doing mauai and the the big island no tour company this time.mama wants to move far from family and HI is about as far as we can. and still be in the usa.

 

I'm quite certain that me and houndog101 are correct.

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C'mon over Charlie! THIS time I'll make sure we meet!

 

Oops! Houndog101 and I.