Hi All, I have a 2002 f250 v10, it has about 90k miles on it. when i bought the truck it was skipping really bad. so i had all the spark plugs changed and found out that two spark plugs were cracked, and one had a heli coil in it. after changing them it ran 100% better but, when it's running at highway speeds it's seems to be fine. when I put the truck into drive without moving, is when it skips. I've changed the fuel filter also. all the coils have been tested and i was told they are all working fine. don't know where to go
from here... any help would be greatly appreciated.
thanks
Brian

 

Don't forget the coils and injectors. Any of those could do the same thing. Beware of Heli coil fixes. V10s like to eject spark plugs and the only good fix is found using Time Sert steel inserts. I've put 6 in my engine.
I would start by investing $20.00 in a can of "BG 40K" injector cleaner. You will need to ask around who carries BG products and it will be behind the counter. Make sure you use it on a full tank of fuel as it has been known to take out sensors if used to strong.

 

Try the crank shaft sensor, I just replaced mine this week 2004 with 115,000, huge difference and I replaced all the spark plug boots, cleaned coil terminals (green and oxidized)

 

Thanks for the info. I have changed all my spark plugs, there is one coil pack that is loose, to where i can move it around, is this normal. should it be loose at all? the others seem to be tight. I did put some injector cleaner in to see if that would help. i'm gonna further investigate the loose coil pack. also can you just buy the rubber boot or have to buy the entire coilpack?? at 50.00 a coil it gets costly when you have 10 cyl.
thanks again all

Brian

 

You can buy just the boots. I replaced all of my boots because a few were cracked and a few were covered with rust. It helped my situation.

 

Just the boots were $4.29 each at NAPA, quite a big savings

 

If the boots don't correct the problem you can always just buy 1 COP and replace one at a time until you find the faulty one.

 

Probably too late but COPs, but at Summitracing.com 8 for $200 NAPA $37 each, I've had a heck of a past week no COPS needed just Os sensors and plugs/boots and Vapor Recovery Solenoid Purge Valve, although I replaced a lot more to get to that point.

 

so far I have changed all the spark plugs, then changed all the boots and springs. and the problem seemed to get better. then i started changing out one coil at a time. I thought that i might have found the problem, ( I only chaged out four of the 10 cylinders) so i stopped but then it's skipping again. so i'm going to continue on changing out the coils to see if there is one that is actually going bad. the funny thing is it only skips when it's in low idle or when i'm traveling at higher speeds after the trans shifts down.(low idle) I appreciate all the input you have all given me, still working on the problem. any other ideas while i'm still working on it??
Thanks

 

The total break down of what I did: (115,000 miles minimal maintance) VSS & OSS codes came up, changed both of them went thru all of the wiring, still got the codes, changed plugs, changed tranny filter and fluid, replaced IAC, cleaned throttle body, had a friend do a live feed on truck O2 sensors weren't great especially downstream one, changed that had 2 wires with shorts in it, was running a little better, changed both upstream O2 sensors, running much better, but still stalling, back to wiring no problems, but codes finally gone, then I got lucky and realized my vapor recovery solenoid purge valve was always out of the canister and I knew I put it back in, no code cause it was hooked to wiring but canister pressure was blowing it out, truck is running great finally after a week and a half (knock on wood) Took the old purge valve apart last night and the thing was completely clogged with dust it is a couple of very fine metal screens and a diaphragm thingy , I bought a new one $100 at dealer
But I would definitely check your O2 sensors, that was my biggest problem