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The plugs were ngk. Replaced with motorcraft. Some of those ports were full of crud. Now it idles normal and revs fine but still misses under any type of load. Not giving any misfire codes, just a p1000 and a code for a blend door actuator and a wiper switch. Got some coils coming in Wednesday. 97 F150 4.6L.
Last edited by quarterpanL; Jul 12, 2025 at 10:57 PM.
Reason: I had one
You’d need a scanner with mode 6 to count misfires.
Those are some pretty dirty plugs. I’d check compression before going all out. Clogged up ports aren’t a good sign. Been there, done that with my 4.2. Fouled up plugs, oily intake, it was a matter of time before another engine was necessary.
I'm willing to go a little further before getting a compression test kit. I could just borrow one from somewhere but I already have the coils on the way. I'll check compression before replacing injectors but hopefully it wont get that far. I can get the truck up to speed it's not terrible but there's definitely something still off under acceleration. I've got the egr blocked off because of a previously unknown vacuum leak by the dpfe sensor that I've since repaired.
I think he was referring to spark plug wells full of crud. It can get past the plug wire "boot" and get in there and harden almost like concrete. Makes getting the plug out a lot more work.
Yea it was cyl 4 I had to stick a screw driver down in there and break up some stuff before I could blast it out with air. The socket wasn't grabbing anything, I had to use a mirror to verify the plug wasn't broken.
I think he was referring to spark plug wells full of crud. It can get past the plug wire "boot" and get in there and harden almost like concrete. Makes getting the plug out a lot more work.
Very well may be. I took that as the EGR ports for the IMRC.
Got the new coils in today and it feels better. I've never driven one of these before so I'm not sure how much of a sluggish hog the 4.6L would normally feel like. It feels torquey at low end and kind of weak at the top, I guess that's normal for this truck? Good enough for me if that means I can pull multiple vehicles on a trailer.
Got the new coils in today and it feels better. I've never driven one of these before so I'm not sure how much of a sluggish hog the 4.6L would normally feel like. It feels torquey at low end and kind of weak at the top, I guess that's normal for this truck? Good enough for me if that means I can pull multiple vehicles on a trailer.
That's about right for operating characteristics with that engine, pulls hard down low, runs out of steam up high.
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