Irregular signal sent to cyl 1 ignition coil

[Haydenaw]

2010 ram 1500 ST 4x4 5.7 hemi with 195000 miles.

Been having cylinder 1 misfire and hemi tick that has been progressing lately. Tried to fix the cyl1 misfire and have swapped spark plugs and coils but misfire continues. I was worried it could be a broken wire or bad connector so I used a timing light on the 2 wires that feed the coil pack. All cylinders flashed regularly while cyl 1 was very erratic. To my mechanics knowledge nothing mechanical would affect the voltage signal being sent through those wires. Wandering if this is what's causing the hemi tick and my issue is electrical or software.

Forum and google search says the signal is sent to the coil from the PCM but can't find much, all threads hear misfire and tick and go straight to roller/cam failure.

1. Is the coil signal truly controlled by the PCM or is there a coil driver somewhere or something similar.

2. What could cause intermittent signal to be sent to a single coil. Could this be a bad flash/program a previous owner did. Glitch in system or physical corrosion/damage in circuit/wiring. (I assume physical corrosion/damage would more likely result in no signal rather than an intermittent one.)

3. I have a obdlink mx+ and alfaOBD. Is there any specific diagnostic I could run to get more info on the issue or cause.

4. AlfaOBD also shows an option to hard reset the ECU. Any idea if this would help and if doing so will mess up anything.

Any help is appreciated, been painful lately getting terrible mileage and power.

 

[jws123]

Not sure about the rest However to rule out cam/lifter failure a quick thing to do is pop the valve cover check the movement of the rocker arm and slack.

 

[Haydenaw]

@jws123
Yes, this is my daily currently but next week I'll have a loaner so hoping to pull both valve covers and see what I'm working with. With any luck all the rockers and springs will be intact.

Some additional backstory on the truck.
I got the truck at 74k and was told other than routine maintenance its never had work done before. Ran great at the time But the previous owner or original dealer had a RCX lift put on, true dual exhaust, and upgraded coils front and rear.
I'm a lil concerned they may have put a cheap flash tune on it that may now be struggling with the age of the engine but I don't have any experience potentially putting 100k + on a cheap flash tune. A d for all I know it could have been none or an expensive one.

 

[KryslerKid]

Hello, I know this is an older thread but I have the same exact problem with 2012 ram in cylinder 5 misfire. Same thing as you where all other coils were firing normally and number five was a sporadic signal almost like firing every other time. I'm wondering if you ever figured out the problem with your issue? Was it the pcm? I'm hoping maybe a bad ground or something. Thanks
KK

 

[RamDiver]

Hello, I know this is an older thread but I have the same exact problem with 2012 ram in cylinder 5 misfire. Same thing as you where all other coils were firing normally and number five was a sporadic signal almost like firing every other time. I'm wondering if you ever figured out the problem with your issue? Was it the pcm? I'm hoping maybe a bad ground or something. Thanks
KK

The OP hasn't been online here for more than 2 years.




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