Hey all,
Ive been searching through the forums, and have a couple things I think may be my issue, but I just wanted to bounce some ideas off the group.
So, it's a 2006, 4.7L , roughly 297000km.
I got a check engine the other day, and noticed it was idling rough. I had 3 codes in memory, 2 codes were misfire on #1, third code was for misfire on #7.
the old girl has what sounds like a hemi tick on cold starts. I replaced the spark plugs about 5000km ago, all of the old plugs were a nice grey or light tan color, no black carbon build up. I replaced the plugs because i had the check engine come on and the plugs ahdnt been replaced for about 60,000. They did need replacing, all the electrodes were wore quite abit and the gap was way out. After replacing the check engione didnt come on until the other day.
The first code was when i changed the plugs, the 2nd and 3rd are from recently.

After reading and clearing the codes, i checked the live data. The spark advance is all over the place. It will go from 9 degrees and jump to 19.5 then back to 10, and over to 13, and around to 15.5 back to 10 up to 17. Is that normal?

I have a theory.
I think it may be a couple things here. I think the timing set needs to be changed, and I may have some lash adjusters out of whack.
My partner said that she had the coil packs changed a couple years ago because she was getting misfire codes back then. So, I dont think its the coils...Im not ruling it out.
But its my theory the computer has been able to compensate for the wearing out timing set until now, and has finally got to the point it cant. now with the "hemi tick", which from my research could be lash adjuster, the computer just isnt able to adjust enough and causes a misfire. Make sense at all?

How do i test the coilpacks?
what live data should I look for?
I will be doing a compression test.
I dont imagine an old school timing light will tell me anything...?

 

First thing to do would be to clear the codes, then move the coilpacks to another cylinder. So swap like 1 and 3 and swap 5 with 7. If the code moves, the issue is the coil. If it stays with the cylinder, the problem is not the coils. If you really wanted to after that you could repeat the process with the plugs (if the misfire stays with the cylinder).

Could be timing. I had a pervasive misfire code on 5 and 7...no matter what I did. Sometimes would show up, other times not. Found out 2 things. 1.) The cowl was letting a lot of water drip down onto those coils. Granted, they are waterproof, or should be, but it did something to them. Also, 2.) I removed my intake manifold and found that at some point in time something melted the inside of the cylinder 5 port. I believe this caused an obstruction enough to add turbulence to the airflow and cause misfiring randomly. I replaced the intake manifold and built a hard to explain "tray/shelf" that I screwed to the cowl. I made it out of galvanized corrugated metal and it basically acts as a shunt to direct any water from rainfall away from falling on the coils on that side. Hasn't misfired since I did those things.

 

Cleared the codes and swapped a coilpack from the misfiring cylinder. No codes yet. but i did get a very short CEL comeon and then off , for the crank position sensor.... But again that was a couple of weeks already, nothing showing up as of late.
I did think of swapping the the timing gear, it just kicked over 300,000km this weekend. MIght be due for a swap, never been done.