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Hey all, I have a 2003 F350 5.4L 2v. Has a slight stumble at idle cold or hot, has a bad misfire up to about 30mph then starts to clear when cold or hot. No codes being thrown, the OBD reader isn't picking up anything either. Advice on the best way to go about tracking down the misfire please. I figured I'd start with new plugs, should I go OEM or aftermarket?
Well I don't think my scanner has a mode 6, so I'll either have to pull each plug or coil individually or replace all at once with no guarantee that is the problem.
Well I don't think my scanner has a mode 6, so I'll either have to pull each plug or coil individually or replace all at once with no guarantee that is the problem.
You may be surprised. Even the really inexpensive scanners will often have it. I have a sub-$20 Launch that does it. It's not always called Mode 6, poke around.
I don't mean this to be as offensive as it sounds, but you'd be a fool to do what you suggest. There's an easy way to isolate the cylinder(s) in question.
If you don't have mode 6 to see misfire counts, pull up fuel trims to see if they are high. Your description could be something simple like a vacuum leak. Check PCV hose. Have you tried cleaning MAF?
Try pulling one of the front plugs and ensure not wet with coolant... Common issue is the plastic crossover pipe leaking on front cylinders.
On this basic Launch 319, rather than "Read Codes" I select the "Diagnose" menu then scroll thru to "OnBoard Monitoring". From there scroll down to Misfire info. You must pull up each cylinder individually on these cheap readers. A "value" of zero means no misfires. Ignore the random max value of 65k-something
This is on a 2V 4.6 in my '07 F150 Look at that beautiful manual transfer case shifter in the background of my '07 F150! The 319 appears to presently be ~$25. The 3001 in the upper right for ~$17 looks awfully similar but I can’t swear it has the same capabilities
I doubt you need a Launch brand to get this. I always figured a $25 reader is basically a $25 reader (I purchased my 319 before the Irrational Global Panic of '20 on an Amazon special for around $13)
Well I paid $70 for the one I have from HF, but it is probably going on about 10yrs old now. Guess it can't hurt to buy a newer model. I have gone through every section I can find and It doesn't have the options you're talking about.
I want to thank you guys for the info you posted. I'll be buying a new scanner in a few weeks but in the meantime I figured I'd let you know the problem was the fuel filter. I decided to let the pressure off the rail and I only got a little squirt for about 1/2 second so I figured it might either be the pump or the filter and took my chances on the filter 1st. After changing it out it cleared up and ran smooth after about 30 seconds. Again thanks for your advice.
I want to thank you guys for the info you posted. I'll be buying a new scanner in a few weeks but in the meantime I figured I'd let you know the problem was the fuel filter. I decided to let the pressure off the rail and I only got a little squirt for about 1/2 second so I figured it might either be the pump or the filter and took my chances on the filter 1st. After changing it out it cleared up and ran smooth after about 30 seconds. Again thanks for your advice.
Good deal. By '07 they had deleted the fuel rail valve on my 2V 4.6 and I need to use my Autel for FRP - fuel rail pressure (never tried to see if the inexpensive Launch lists this PID)
If you don't have mode 6 to see misfire counts, pull up fuel trims to see if they are high. Your description could be something simple like a vacuum leak. Check PCV hose. Have you tried cleaning MAF?
Try pulling one of the front plugs and ensure not wet with coolant... Common issue is the plastic crossover pipe leaking on front cylinders.
The fuel trims were -3 and -7. I rented a pressure gauge, key on engine off it sits around 22psi and drops about 2psi every minute. Engine running is from 25 to 28psi, If i rev the motor It will get to about 36psi with the FPR unplgged, then starts settling at around 34psi. So is it FP or FPR? I'm mean it starts with the 1st hit of the key but it sounds like it's running on 6 or less cylinders the FPR doesn't have any gas coming out of it or the line. Thoughts?
UPDATE....
So I decided to disconnect the battery and clean the posts up. Then I removed the MAF to clean it up. I unplugged it and removed it. I decided to start the truck thinking it would throw a code and light...I revved the engine pretty good but it seemed to run better. Shut it off, reassembled everything restarted the truck and its running smooth. Took it around the Block and goosed it pretty good, and it responded well. I know i cleared the memory but this is strange to me. Im wondering if i had a clogged injector that cleared or if itll return once the sensors reset?
Just an update...The fuel filter didn't work, The fuel pressure as stated before was low but then it was consistently up there between 38 & 42 PSI. I bought a new MAF because the old one was only registering 0.02, but the new one is only registering 0.01. All coils are working, all injectors are working. My next step is to remove coils which is going to be a PIA, the bolts seem to be spinning So I'll have to either try to cut the bolt heads off or cut the coils off. Then try to remove the spark plugs without snapping them. Hopefully no coolant will show up in the cylinders.
Just an Update on this thread to close it out. I replaced all of the coils and plugs Cylinders 3,4 & 8 were a bear, but I honestly don't think the PO had ever changed them and with 137K it was time to get it done anyway. Truck is running the way it's suppose to now. Thanks for all the advice.
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