misefire?
Thread Starter
|
Junior User
Joined: Aug 2008
Posts: 52
Likes: 0
misefire?
Hello again!
I have a 2001 F250 4x4 with a 5.4 automatic. The other day i was going to work and the truck seemed to have a little studder/buck in it. So i returned home and borrowed the wifes car. When i returned home that evening i went for another run in the truck and noticed the same thing. I proceeded to add a bottle of gas line anti freeze and went on another test drive(really cold here lately). As i test drove the truck this time, i probabley drove it harder than i ever have before. I never noticed anything different( it worked perfect then and still now) but when i got home, the truck seemed to develope a misfire that could only be noticed through the exaust. Made worse by a whole in the muffler. I went to a friends house that had one of those snap-on scanners and he hooked it up . The machine showed a misfire on number two cylinder. So far i've replaced the coil, switched injectors, replaced plugs to no avail. the only thing we noticed during the whole process was that the number two plug was very lean. It was snow white. The couple of others i changes were tan brown. To drive the truck, the miss it not noticable.
Anyone know where to look for this? Ideas of what it may be?
I had a 01 f150 that had a problem with one coil on damp days and when it was a problem, the truck would shake the **** out of you when it got in overdrive.
I have a 2001 F250 4x4 with a 5.4 automatic. The other day i was going to work and the truck seemed to have a little studder/buck in it. So i returned home and borrowed the wifes car. When i returned home that evening i went for another run in the truck and noticed the same thing. I proceeded to add a bottle of gas line anti freeze and went on another test drive(really cold here lately). As i test drove the truck this time, i probabley drove it harder than i ever have before. I never noticed anything different( it worked perfect then and still now) but when i got home, the truck seemed to develope a misfire that could only be noticed through the exaust. Made worse by a whole in the muffler. I went to a friends house that had one of those snap-on scanners and he hooked it up . The machine showed a misfire on number two cylinder. So far i've replaced the coil, switched injectors, replaced plugs to no avail. the only thing we noticed during the whole process was that the number two plug was very lean. It was snow white. The couple of others i changes were tan brown. To drive the truck, the miss it not noticable.
Anyone know where to look for this? Ideas of what it may be?
I had a 01 f150 that had a problem with one coil on damp days and when it was a problem, the truck would shake the **** out of you when it got in overdrive.
New User
Joined: Feb 2009
Posts: 1
Likes: 0
From: big island , hawaii
rough idle
there is a vacumn hose underneath the throttle body. it is a tricky fix. i have seen it several times. on different vehicles. remove your air cleaner and housing. remove the air duct to the intake. reach your fingers underneath the intake. you will feel the hose. it will most likely be collapsed or have a hole. funny most ford dealers stock this stupid little hose. good luck. any questions let me know.
Thread Starter
|
Junior User
Joined: Aug 2008
Posts: 52
Likes: 0
There's no cel on. Yes it's only at idle. I will check what you suggested later today and get back to you. What about the white powdery plug and the scanner indicating a miss on the number two cylinder? If i had a bad cylinder(hope i don't)would that scanner indicate a missfire. One more thing. Iwas talking to a very reputablemechanic in my area and he said if it was a valve or something, the cylinder would be rich and the plug would be black because the gas would not be burned.
Trending Topics
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
Good point about the lean vs. rich.
I'd check if the injector is being fired by the PCM - with a DVM on AC, hook it to the injector connector and see if you get any voltage there.
Also, you could be coming up against a strategy in the PCM where if it detects enough misfires, it turns off the injector for that cylinder. But, it's a Superduty, so I don't think it would do that, and besides, you'd get a CEL for that I believe.
https://www.ford-trucks.com/forums/5...t-come-on.html
I'd check if the injector is being fired by the PCM - with a DVM on AC, hook it to the injector connector and see if you get any voltage there.
Also, you could be coming up against a strategy in the PCM where if it detects enough misfires, it turns off the injector for that cylinder. But, it's a Superduty, so I don't think it would do that, and besides, you'd get a CEL for that I believe.
https://www.ford-trucks.com/forums/5...t-come-on.html
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
