99 SuperDuty Rollover

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Oct 19, 2007 | 04:16 PM

pdc666

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99 SuperDuty Rollover

F250 SD 5.4 Gas SRW 4x4
2.5 yrs ago, truck was rolled thru a ditch into a tree , every panel except hood and tailgate fubared. Last fall we stripped it to the frame and started over. New cab/clip/ and fab'd a flatbed to cover the new dually rear tires. Truck has 155k/90m on it. Got it on the road last week. Have a stumbling issue when truck is in OD(4th)- turn OD off truck runs way smoother?- also seems to want to twist to 4000rpm while shifting into 2 & 3?
I do have a mechanic who scans it regular but nothing really shows up. Replaced the cat today, will do platinum plugs mon.
Any good ideas would be helpful. Thank you all in advance.

Oct 19, 2007 | 04:41 PM

hydro_37

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From: Iowa

Check the VSS on the rear end.

Oct 19, 2007 | 11:31 PM

mattd17

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From: Ketchikan, AK.

sounds like a bad cop..... the 5.4 is common to do that !!!

Oct 24, 2007 | 07:41 PM

pdc666

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Update: Changed ABS sensor and fuel filter, added octane boost no change. Scanner said #8 misfire- pulled 2 & 8 found 1 good plug replaced other swapped coils--drove it for an hr ---scanner said #5 misfire, pulled 1&5 found 2 good plugs and 1 unbolted coil on 5, swapped coils. rescan= zero codes, cleared codes, dbl checked.Truck was perfect for 15 mins of driving then felt it stumbling, ...........scan says #5 misfire again!!!??? Bad plug?? it looked mint-dbl platinum no less. Help
On the plus side a 96 PSD IDM will work in a 2000 PSD even tho stealership says NO! They wanted $1100 CDN for the part . I took it off another truck in the yard that is being slowly parted out. My cost = $0000.00

Last edited by pdc666; Oct 24, 2007 at 07:46 PM.

Oct 24, 2007 | 08:02 PM

mattd17

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From: Ketchikan, AK.

it really sounds like you have a bad COP.... they dont always throw a code when they go bad.... and as for testing them, its really hard. you can measure the restsiance on them, but you have to do it warm, since the resistance will change as it warms up. have you checked the rubber boots? does one of them possibly have a crack in it, and the coil is shorting to the head? just another quick thought.

Oct 24, 2007 | 08:06 PM

pdc666

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All 4 boots were undamaged, the insides were not corroded or rusty. I agree w/bad cop but which one? The misfire seems to migrate. UAP cop's are $96 ea, I missed a set of Accels on ebay for $200. Change all 8 and be done w/it?

Oct 24, 2007 | 10:28 PM

mattd17

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From: Ketchikan, AK.

noo.... i wouldnt change all 8, unless of course you want to waste money. i will say also that these 5.4's seem to only like motorcraft plugs (or autolite). thats about it though. so, that could be an issue as well if your running a different type. at this point, with 155K miles on the truck, how old are the plugs? i would start there as the cheaper fix.... double check the gap, and also make sure the rubber boots are good, and coat them in some di-electric grease when you install them onto the plugs. a big problem on these engines is the #4 COP, due to the water hose fitting directly above it. what can happen over time is it will leak, and the coolant will go straight down onto the COP, and can short it out. i am curious about the brand of plugs that you have in it now though. also, i have a spare brand new OEM motorcraft COP from when i had my superduty, if you would like a spare i will sell it to you.