2000 F350 v10 bucking/ shuddering at low rpm uphill
goes away when I punch on the gas pedal.
have only had the truck for a few days, tested coil packs and changed fuel/ air filter to no avail. No check engine light on, going to pressure test fuel system this weekend. I’ve read plugs are hard in this motor? Is there a way to test them? Don’t have a reader to see which cylinder is misfiring- if that’s even the case. They are motor craft (sp?) plugs in there now. Anyone had this issue and resolved? Anything else I can test before I start pulling sensors etc? Thanks!

 

Start with plugs before you melt a cat. Your symptoms are common of worn plugs.

 

It's also common that the boots between the coils and the plugs fail. There is no way to test the boots, just replace them. I paid about $4 each from Rockauto.com.

 

Sounds like a case of misfiring under load, I would guess degraded plugs or boots.
How many miles on the plugs & boots?
It takes a lot misfires to set a code, but there is data that can be accessed to tell if a particular cylinder is misfiring.
A standard code reader can't access the data, but an OBDII port adapter and Forscan software can pinpoint a misfiring cylinder.
Long term misfiring can ruin a CAT.
Definitely check the fuel pressure.
If the plugs or boots have more the 50k on them I would change them (under $100) before digging into any sensors.
Yes, changing the plugs is tedious, but there are a lot info/tips/pointers in these forums.

 

Totally the plan. Going to test fuel system this weekend, luckily it’s not my daily driver. Unsure how old plugs are, just bought it 3 days ago with no history. If the fuel system checks out, will order plugs and boots and maybe a coil pack just in case. I’ll update as I complete things. Thanks for the reply!

 

Consider getting yourself a tube of dielectric grease too. Use it on coil pack to plug connections, and any other electrical connections you disconnect for repair. Keeps moisture out of connections, and eases disassemble for the next time you need to disassemble.

Also, use M/C plugs. Not sure about the 2000 model year, but having the Lisle plug removing tool handy could save some headaches.

 

His 2000 is a 2v which uses the old style one piece plugs, the Lisle plug tool is for the OEM two piece plugs used in the 3v motors, 2004+.

 

True dat, but I am not sure what version of Forscan gives Mode $06 by-the-cylinder misfire counts, if any. I have a 1999 F350 with a 6.8L v10 with about 250k on it that started misfiring a few months ago. Anyone with this problem knows it drives you 'nucking futs until you can cure it. You find yourself gazing at used truck ads and praying this truck will not leave you stranded in Harlem. I tried a lot of fixes, including checking coil on plug (COP) resistances, gapping the newer spark plugs, check fuel pressure, change fuel regulator, did a compression check, changed the fuel filter, ran SeaFoam thru it, god knows what else. All to no avail. Same misfire under load. It would run fine at idle, then start missing badly between 1500-2500, then clear up at higher rpm. Thinking it sure acts like a faulty coil, I did some interweb surfing and learned that worn COPs may fail only at certain loads and rpms, making resistance a nearly useless test. So I downloaded the current version of Forscan from their website and checked the Mode $06 data. I did get a lot of useless facts like Type A and Type B misfire counts and so on, but Forscan does not offer what you need. You need by-cylinder misfire counts so you can pinpoint which cylinder is bad. I then learned only the more expensive scanners can do it. They can supply a cylinder misfire count by cylinder and a power balance graph to show which cylinder is doing what. Snap On Solus, Ford has one also. My mechanic put a Snap On Solus on my truck and had the offending cylinder pinpointed in 2 minutes. Got home, slapped a new COP on it, truck runs like new. Now it's beer thirty.