Misfire detected code, but coil pack and spark plug is firing... please help!

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92ShoOff

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Hey everyone, my the top end of my '96 is torn apart and I need to get it back together and running tomorrow. Earlier this week I started the car up, immediately got a check engine light, and drove the car to AutoZone to have them read any codes. We got the following code: P0301 - Cylinder misfire detected, cylinder number 1

I was unsure of the maintenance history on this 160k mile car that I've put less than 10k miles on since buying it earlier this year. That said, I figured it could use new plugs, and I purchased one coil pack, to use for cylinder number 1.

The intake manifold on the Gen III is a TOTAL pain to get off.... mainly the surge tank that sits over the rear valve cover. I was able to have my Gen II intake manifold completely off in less than 25 minutes-- this ones has taken me many hours. haha.

So I replaced all of the spark plugs all the way around and I tested the number coil pack for spark. The new coil pack of course sparked just fine. But just to see if the old one was the problem I plugged it back in and checked for spark. The old coil pack sparked just as strong as the new one. Now I'm not sure if doing all of this work has solved anything.

I manually triggered the #1 fuel injector to make sure it was spraying. I had an extra harness from testing injectors on my Gen II injectors, and it of course connected to this fuel injector just fine. I connected my leads to a 9 volt battery and the fuel injector sprayed. All of the coils on the firewall side of the engine are firing.... and I'm not sure if my problem is solved.

Now, I do think that I may have heard something drop out of the number 1 coil pack boot when I disconnected it from the spark plug. The tip of the spark plug was intact, and I couldn't really notice anything broken off on the inside of the coil pack. It could have been the noise of something else (debris) falling off the rear valve cover area when I dragged the coil pack out, so I can't say for sure where whatever fell out came from. Is it possible some debris has been or has recently broken off and gotten lodged inside the coil pack boot and caused it to throw the code??? And maybe the debris is what fell out and is now allowing the coil pack to work again? Or is there nothing inside of the coil pack boot to really break off or anything?

PLEASE help me out with this ASAP... I'd really appreciate it. I have somewhere very important to be very early Monday morning and this car needs to be drivable tomorrow night. Thanks!!!!!!!!!
 

Fahrzeug

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I recently had a F-250 in with a V10 and had a Cylinder 9 misfire. After all the checks, tried a new coil and plug, and checked injector function. Which you already did. The last step would be checking compression on that cylinder because Cylinder 9 on the F-250 had 25psi of pressure and the others were all 100-125psi. Lets hope it's not a compression issue. :omg:
 

SHOZ123

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Could be too the coil wires laying on the valve cover are shorting out. They tend to melt if they lay undisturbed for a very long time.
 

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