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Misfire - mostly under load. Been going through it.
Hello all,
So I just did an insane amount of work on my truck, damn near restored it by this point, and am having another issue that I was wondering if anyone could shed some light on....
Truck is 98' F150 4.6 4x4 5speed manual. 152k miles
Problem:
The main issue is that when under load the truck develops a bad misfire. When I say under load I am referring to accelerating at low rpm with more than 1/3 throttle. If not under load everything seems to be relatively ok.
Without going into a long explanation, a good portion of the EVAP system is gone. I was wondering if the pipe in the pictures being broken/open could be affecting this? It clearly would be causing a vacuum leak, but I don't know if this could be the culprit.
I have already replaced spark plugs, ignition wires seem ok (but I will look again), injectors were "flushed" but not replaced......
Thoughts on where you guys would start looking next?
Much appreciated. I'm sick of working on this thing, dumping money into it, and still having issues that are keeping me from really using it.
Not the best photo, but if you look to where i'm pointing that is the line that broke and is now open. Trying to point to the same line as in the first picture, but from a further out view.
Truck is 98' F150 4.6 4x4 5speed manual. 152k miles
Problem:
The main issue is that when under load the truck develops a bad misfire. When I say under load I am referring to accelerating at low rpm with more than 1/3 throttle. If not under load everything seems to be relatively ok.
I have already replaced spark plugs, ignition wires seem ok (but I will look again), injectors were "flushed" but not replaced......
Is the CEL/SES light on? Have you checked for codes? There's a lot of information in the codes.
You might describe more about the misfire. Does it still accelerate at a decent rate, just with the feel of misfiring? Or is it low on power and slow to gain speed?
So there was no CEL and I had not checked for codes. I did actually figure it out though. It turned out that the coil packs and ignition wires were trash. I replaced all of the above and it's running great now.
I do however have another issue that has been plaguing me since I started this whole build/rebuild about 2 years ago though. It has to do with a bad vibration under acceleration, and isn't anything obvious. I will post this in another thread though so as not to mix topics.
That is the EGR tube you are pointing to
Has the two pipes that go to the DPFE sensor
1 bigger and 1 smaller, that is the pressure differential between the two hose sizes is what the sensor uses
I'd replace the broken EGR tube, before you cannot get one easily
Have patience, spray the big nuts with rust penetrant, use a torch to heat them up and then try to loosen them
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