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Intermittent P0301 code

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95PURPLEPEEPLEEATER

Probationary Member
5
1
Mar 18, 2020
Salem, Oregon
Hi, new to this forum and brand new to dsm's. I got a 95 eagle talon tsi with the 4g63 in her a few weeks ago. This forum has helped me tremendously with questions and a few bugs I've worked out of it already so thank you for that! But this bugs got me by the balls. Very mechanically inclined and have done quite a bit with almost anything with an engine under my seat. But intermittent problems bend me over..

95 talon tsi 113k miles
Arp headstuds
Resurfaced head
New headgasket
Intake gasket replaced
Injen recirculating intake
Brand new 02 sensor about 200 miles ago

Other than that the rest of the engine is stock as far as I know. Compression in all 4 is within 8psi of each other.

Heres my dilemma. Driving to work yesterday am cruising ~ 3100 rpm I get a CEL pop up and I lose most my power. Starts sounding like a subie (i knew misfire right away). I pulled over and plugged my mobile scanner into her and I had a cylinder 1 misfire p0301. So needing to get to work i just pop the hood make sure plug wires are all on tight and clear the code and hit the interstate again. About 5 miles and it hits again. So I call it a day and clear the code again and start to head home. I pulled off pry 3 or 4 times to clear the code until I say eff it and limp it home with the misfire. Park it and take my other car and got new plugs and wires for her. Get home to pull it in the garage and swap plugs 1 and 2 as I read a member on here suggested to do that and then try switching wires to pinpoint your issue. So I swapped the plugs cleared the code and took it for a drive. Ran fine. Swapped the plugs back to the way they were. Drove it for pry 40 miles. No cel ran fine. Swapped 1 and 2 again. Drove it and ran fine.

So being as particular and paranoid as I am I want to pinpoint the issue I had but cant get it to do it again. Its mentally messing with me. I know most of you reccomend copper ngk plugs (BPR6ES) and that's what I got. That is not what the previous owner had in the car I think they were platinums, would have to pull and look. Should I just replace them and stop worrying or am I missing something? Any advice helps!!

Thank you all.
 
The fact that it was a P0301 and not a P0300 is a good clue. If it were in the ignition system, you likely would have found it by the steps you've already taken. Ignition system issues on a waste-spark system almost always causes both cylinders on the same coil to misfire. I would image you have a damaged wire in the circuit for injector #1.
 
Hmm so your thinking more on the fuel side than spark? The harness for my fuel injectors looks replaced, much newer sheathing and plugs, compared to the rest under the hood. Maybe previous owner did some jankey wiring job under that sheathing? I will go out right now take a look and report back. Thank you!
 
Found a small nik in the wire from fuel injector 1 here, I will fix that but man I pulled my panel and looked at my ecm pins and you pegged the nail on its head! Saw this and my neighbors pry think I'm nuts soo stoked! Thank you soo much!!!!!!! Gonna fix the rest that are chewed up and loose but man that totally puts my mind to ease you have no idea. Thank you again!!!
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Even though it's worth patching those up to make sure they don't fully fray up, they look perfectly intact and the majority of the wire is still getting sufficient signal/electricity running through it. I highly doubt those two wires are your issue.
 
I was looking at the green wire on my ecm that the pin is poking out of the plug. Still think that's probably not it? Thanks
 
That green that poking out is for the #1 injector. Make sure it's plugged in all the way.
If still suspect, you could disconnect battery negative, unplug that ECM connector, test continuity (see if get digital multimeter constant beep {continuity setting} or analog multimeter needle deflection {ohms setting}) on that pin to injector #1 connector while bending that ECM connector green wire around.
 
Ok I got it snugly in there will do a continuity test on it to be sure shes good. I found the ecm pinout on the forum as well and saw it was injector one. I pulled it fully out and started the car and got the same p0301 code so I'm hoping that was the culprit. Thank you!!
 
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