So, how much ticking are we talking about? When the engine is cold, it's ticks like a timebomb. Picks up speed as the rpms go up. Sounds really loud now that I have the soft doors on. Doesn't matter if it's cold or warm outside.
After a minute or so, it doesn't tick anymore.
Is this what we are talking about?
This sounds to me that your hydraulic lifters are the problem.
My check engine light/ ticking was happening well before the ECO light stopped coming on.
I do not think that ticking is from the injectors. Yes the injectors do make noise but the ticking I was experiencing was more of a valve chatter. And it didn't start till I had about 8 thousand miles and at cold starts it was really noticeable. And the valves for the #2 cylinder were "burnt up" according to the tech that is working on my jeep.
Just picked a buddy from Jeep, same diagnosis following engine light and rough idle on his '12 Grand Cherokee with penta & 24K on clock. Tech told him 81 vehicles are ahead of him to receive the backordered parts nationwide as a result of a STAR inquiry (tech website). Among the parts was a right side head. Hold long have guys been down?
OME lift 619/617, JKS front trackbar & rear trackbar & brace, Procomp 7005 & 285/70/17 Duratracs, AEV Procal, Poly Perf. Frt LCA's, Rigid D2's, Vision X Solstice on rear
So I definately have the same noise. No other issues, no light. Took it to the dealer they acted like they have never heard of this issue. But it's documented. Runs fine for now, build date of 9/11.
It'll get louder in a few thousand miles. You'll notice your gas mileage drop a bit then the check engine light will come on and it'll throw code P0304 or P0302. Then you will take it to the dealer and they will just flash the computer and give you "that should fix it, but bring it back if it happens again". The light will probably come back on while you are driving home. You'll take it back and then they will probably replace the head.
Mine has over 19,000 miles noise is not as loud as before. Build date of 8/11
2012 Unlimited Rubicon Cosmos Blue
The small things that you come across everyday, The norm that's overlooked until it is unseen, then when that comes you miss life, one thought, one smell, one sound can take you back home, then you realize your a thousand miles away, and then you get sick....