Hello Scotty, I have a 2000 Ford Excursion, 6.8L V10, 4x4, with 278,185 miles, and it has intermittent misfires going on. I have replaced the spark plugs with NGK Irridium plugs, the coils with Napa brand coils, all 10 injectors with new factory Bosch injectors. The misfires happen during idle, and really any time I'm not on the throttle, but clear up when I am on throttle. I was thinking it might be the fuel filter, but am not sure. The engine was running perfectly until recently, smooth, and loads of torque. Can you please lead me in the correct direction?
Why did you post this THREE TIMES? That is a violation of forum rules. (Another moderator deleted/merged the extras.)
Wasn't intentional, my phone was not responding, and by the time the post had gone through, it seemed to post 3 times
The site can be sluggish, please wait for it and do not repeatedly hit the submit button as it leaves a mess that moderators have to clean up. Thank you.
Noted, and sorry, like I said, wasn't intentional.
No problem, just wanted to make you aware of it. People do sometimes inadvertently post duplicates because of site lag. Normally if there's just one duplicate and there are no answers yet we just silently delete the dupe, but this one was a bit messier.
Wouldn't that throw codes though? Only reason I ask, is that there is no check engine light, and no codes thrown on an OBD scan.
Check ignition timing with the engine running using a scan tool or a timing light as Scotty demonstrates. If timing is not stable you have timing chain wear.
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https://www.youtube.com/watch?v=3zyjyVUoe6c
Timing. You have eight miles of timing chain & plastic guides/tensioners. Be happy it made it this far, they're supposed to get changed out at 150k.
Wouldn't that throw codes though? Only reason I ask, is that there is no check engine light, and no codes thrown on an OBD scan.
Not if it's below the limit, it can act up & still be "within tolerance".
This is an interference engine so I'd take care of that before the warning signs become valves hitting pistons.
I'll have to take a look then
Have someone with a pro-level tool or forscan run a graph.....even on a basic walmart tool it should tell you how much timing you're running.
Compare those numbers at idle against what you are supposed to have.
The other option is popping off a valve cover & reaching in to feel for slack. You'll feel slop. I'm unsure if triton valve cover gaskets are reusable but even if you have to buy one, maybe it'll take you 30mins & cost $20 instead of $140/hr diagnosis.
Issue isn't timing, it was the catylitic converter, some druggie decides to take the one that my truck had, and it's been fine since.
That was a big chunk of info to leave out....
Yes... Your fuel filter can be the cause. The fuel pump, maf, map, motor mounts, idle control valve, iat, bad battery and alternator. Even the belt tension. These are some of the possibilities. First I would check motor mounts then change the fuel filter and check the fuel pressure. If that doesn't help I would look into the idle control valve . From there I would double check the coils are good. Just because something is new doesn't mean it's good. If problem is still there I would just go down the list from there. If you have a scanner that reads live data go online and watch videos how to read live data and how to diagnose. That will really help you norrow it down.
I forgot to add, there is no check engine light on, or codes showing on OBD scan, does that help any?
Found the problem, since someone decided to steal the catylitic converter off of the truck, it hasn't been misfiring at all. Makes me believe that the cat was bad. When I got this truck, it had a check engine light due to a lein condition, and no idea how long it was running like that. Looks like a new cat converter is going to be the fix.
faq
Hello Scotty, I have a 2000 Ford Excursion, 6.8L V10, 4x4, with 278,185 miles, and it has intermittent misfires going on. I have replaced the spark plugs with NGK Irridium plugs, the coils with Napa brand coils, all 10 injectors with new factory Bosch injectors. The misfires happen during idle, and really any time I'm not on the throttle, but clear up when I am on throttle. I was thinking it might be the fuel filter, but am not sure. The engine was running perfectly until recently, smooth, and loads of torque. Can you please lead me in the correct direction?
I forgot to add, there is no check engine light on, and no codes on the OBD scans.
Try cleaning or replacing your MAP and MAF sensors.
You won't always throw a code. When sensors fail it has to meet a certain criteria and fail percentage before it's trips anything. Some sensors won't throw a mil till its below 70% efficiency.