I'm fighting a misfire on #1 cyl. plugs had 80,000 too big of gap so put new plugs in wires are fine, coil test good with spark test, but put known good coil on anyway, fuel psi good, even changed plug with other cly that wasn't misfiring, Ohm coil, and injectors, 190lbs compression, did injector leak down, checked to make sure pcm was pulsing injectors, took off plentum and pulled injector rail, checked to make sure they were spraying, check each one, spray was same all the way across, can't find anything yet so took off back valve cover, looking for valve spring problem, everything looked good. any help would be appreciated, A friend of mine works at chrysler dealership, said he had one one time doing this, and found egr valve causing problem, Probably my next move, I' lost at this point,

 

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I'm at a loss. It looks like you checked compression fuel and spark. Not clear on the plug wire for #1. Did you swap it? This website lists other possible causes that have never made sense to me but, who knows: http://www.obd-codes.com/p0301

 

I agree, move the plug wire. It may ohm good, but under a load of trying to fire the plug, it may fail.

 

Plug wires were second thing tried, Put three different known good wires on, Today we done compression comparison, and #1 is around 180, all of them are around 160 or so,, Gauge seem to jump up different on #1 a couple of times, so pullled valver cover back off and took off rocker rail to make sure they were't wore, also took off springs to make sure valves are not binding in guides. I tell ya I am lost, everything looks great, Only counts misses on idle to 1200 above 1200 runs smooth and shows no misfires,, runs great down the road with no misfires, misfire at idle will turn light on too.

 

Have you tried swapping out the injector with another cyln?
Since you suspect EGR, just Remove the Tube from the Intake manifold and Tape the hole off, see if it miss. If it still miss, it is not the EGR valve.
I've had stuck PCV valve causing Misfire. Try pinch off PCV valve hose.

Try run some Carb Cleaner thru the cyln see if it can clean things up in cyln 1.
Cylinder one is the Passenger side rear bank, right?

I also have one with "SLIGHTly" leaking head gasket. Only miss at Cold idle. I threw a whole Bunch of things at it and pulled my hair out. (waranty) Ran compressed air into the cylinder on cold engine, I see bubbles coming up the radiator cap.

 

Yes, today also took off injector rail and swapped injector with another, same result, checked pvc valve, clean and rattles put finger over it and it suck up and fallls when let go. also took of tube and put plate on intake, same , miss on idle and runs great driving,

 

You may have either a burnt valve on that cylinder or a bad valve seat. The only way you will know is to remove the cylinder head and inspect. Do you have a service contract?

 

Do a Voltage Drop test on the fuel Injector Circuit.
Stick a Test light into the Power wire on the power side of the injector connector to light up the test light, and Use you Multimeter, set it on Voltage, and stick one lead to B+ of battery, other end to the needle of the test light. See if you get another resistance(voltage drop) across the Injector Wiring.
This happened to me by on a Toyota once, High Resistance on the wire.
Or you can OHM out the wire from PCM to Injector and Coils. if that's easier.

Just trying to rule out electronic side b4 u tear down the engine. Or see if Combustion Chamber cleaners may help u clean up some Carbons in the cyln. Altho i never had luck with them.

I am fighting a Charger with cyln1 Mis on start up now. replaced coil and plug twice, injector once, and did a Cyln head last week. She just drop the car off yesterday with same problem. I am ready to crash it into a light post.

 

we did pressure test on injectors and also cranked engine over with injectors pulled out of intake testing them with pcm firing them, ohm them and all were about same, did leak down test on #1 and 3, both were right at 0 % leakage.