LeClarion,

How many miles do you have on the O2 sensor? Are any codes set? Note the SES light doesn't always turn on when codes are stored in memory. Does the mis start as soon as you change the plugs or does it take a while to come back? Something is causing the plug to melt. Either the plug is too hot, wrong heat range, or the combustion temp is too high. A lean A/F mix will cause the temp to rise but hot enough to melt the electrode should set a code.

JMC

 

Previous owner says he changed them, but I don't know. If he did, then I've got about 75K on them, if not, 165K. The misfire starts immediately, the truck is actually VERY hard to start, it's now behaving more like the dead cylinders are not firing at all. I have four trouble codes:
P0113: IAT Sensor 1, Circuit High Input
P0302: Cylinder 2 Misfire Detected
P0305: Cylinder 5 Misfire Detected
P0307: Cylinder 7 Misfire detected


These are all current codes. I scanned, cleared all codes, drove it one mile or so, and scanned again.


The plugs are the specified replacements, factory heat range, correctly gapped(when gappable), all that good stuff. At this point, I don't think anything BUT a severe lean condition could cause this. Here's what makes me wonder, though; I have misfires on 2, 5, and 7(If misfire monitoring is to be believed). On cylinders 2 and 5, the wiring connector for the fuel injector is very loose, I can pull them off just by tugging lightly on the wires. I think they're broken, but I can't see anywhere on them that shows signs of broken plastic. Could this be affecting my truck, somehow causing the injector not to fire correctly? Also, just out of curiosity, is this truck a batch-fired setup, or is it sequential injection?

 

The Motorcraft is the one in the middle that has 60 thousand great miles on them - I can't beleive you can't see the Auto Lites on each side, the pictures clear..?? - There both distorted in color , it's obviouse they got hot after just 40 miles..Well, your the first one who didn't notice this right away after I posted these pics. U ok dude? No offense, but if your colorblind say so , that would explain your reply..

I've come across allot of misfire issues but never one like this , I can't help you - hope someone else can..

Good Luck

 

Ah. I didn't see the distortion, they looked pretty much identical to the ones I had sitting on my desk that hadn't been installed in a motor. My mistake.




Well, I'm replacing all eight injectors tomorrow, so here's to hoping that solves the problem. I sure hope so, 'cuz I'm using this beast to tow my 1993 Chevy Lumina Euro up to town for a motor swap, and I don't want to have to do that on a misfire.

 

ARGH....

I replaced all eight injectors with brand new units, and nothing! I took the truck back to an Advance Auto Parts store, and scanned the codes, came up with the same ones. I cleared the codes, drove it about 10 miles. The MIL came on and started flashing, so I went back to the AAP store, and scanned again.

P0302- Cylinder 2 Misfire.


So, the cylinder that I pulled the melted plug out of is still misfiring. I've now replaced the fuel injectors, spark plugs, wires, coil packs, and just about everything else. I put a tester on the wire, and it's definitely getting spark TO the plug. I don't know how to test to see that the injector's firing, anyone here know how to? That's what I'd like to do next.

 

Mmmmhhh that plug looks similar lol. To bad my truck is STILL missfiring

 

I can tell you with fairly good accuracy that the injector for that cylinder is injecting fuel.
Why, because a flashing MIL lamp is telling you the cats are seeing unburned fuel.
The plug isn't firing for some reason.
Are the boots in new condition?
Did you grease the boot tips so they find and slide onto the plugs easy and not jamb off to the side?
Try this to get a relitive test of the coil.
Remove the injector plug so it dosn't inject fuel.
Pull the coil loose and apply a plug to the boot tip such that it fires the plug to the engine block. Start the engine and observe it.
It will only tell you if the coil is able to fire and not anything else about it's condition otherwise.
If no fire, be sure it is being pulsed by the PCM by checking the voltage, using a NOID LITE at the connector or replace/sub the coil.
You only have the plug, coil, boot and the PCM driver/wire harness as a possible fault for one cylinder not firing unless the cylinder has a stuck/burnt valve etc. Then a compression test is in order to see that.
These tesing conditions might bring on other codes so clear them and see what keeps coming back so you don't get confused.

 

Got my miss cured( I hope) Was getting the code P0303 but the miss was sometimes gone.Dropped the truck off at one mechanic and he told me my head gasket was shot( Was never low on coolant,Didn't overheat or blow white smoke) and he said it would cost between 1400 and 2000 bucks.Said "NO",After re-replacing all the plugs and wires I still had the miss. Replaced the fuel filter then both coils still had a miss so I started pulling one injector plug at a time while the truck was running and found that ther was no change when I pulled # 2. Put a new injector in and she runs nice and smooth with no miss,So I guess I had 2 separate problems, A bad plug,wire,or coil and a bad injector.

 

Did what you said, Bluegrass. I'm getting a solid spark at the plug. Just in case, I replaced the plug, wire, and coil packs again, just to be on the safe side. I didn't think it was a coil-pack, since they fire 4 cylinders, and I'm only having issues with one, but I figured I'd try it anyways. Well, didn't help. So tomorrow it goes to a stealership, to see if they can diagnose it. If they can get a decent diagnosis for me to work with, hopefully I can do something with it.