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Discussion Starter #1 (Edited)
2012 Grand Cherokee 5.7 Hemi. How hard is it to change the plugs and what are the steps? Any plug recommendations? Power Block TV sure recommends E3 (sponsor?) but dyno says more power. What else consists of a tune-up on this model?

On start up, usually warm now that I think of it, it sputters coughs chokes and dies. If it is hot I have to turn AC off.

Adding fuel system cleaner from Jeep tonight....
 

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Discussion Starter #4 (Edited)
NICE! Thanks. Motorweek dude said that the spark plugs need to be loosened, then re-tightened. Start engine and rev it out a bit to blow out loose carbon or you can damage the threads in the aluminum head. Then replace the plugs. What a hassle on direct on plug coils and 16 plugs! And maybe why $800? Necessary? I definitely have the know how to do this, even before I asked, and the "skills" to really screw it up (why I asked! LOL)
 

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the loosen-tighten-start-rev-remove sounds like a pile of crap, IMHO of course.

Also, IMHO, E3's are junk. I would avoid the "fine wire" platinum/iridium plugs as well based on my experience with other engines.

IIRC a '12 5.7L would have left the factory with plain ol' copper plugs (NGK 92714/LZFR5C11)..
 

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Discussion Starter #6
The engine problem was due to the 2015 Recall of the Fuel Pump Relay. They said the new one was bad! They did the Spark Plugs and Fuel System Clean for $500 plus new Renegade loaner. Would have like to save the money and do it myself (both) but whatever could have gone wrong would have and cost me more.
 

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NICE! Thanks. Motorweek dude said that the spark plugs need to be loosened, then re-tightened. Start engine and rev it out a bit to blow out loose carbon or you can damage the threads in the aluminum head. Then replace the plugs. What a hassle on direct on plug coils and 16 plugs! And maybe why $800? Necessary? I definitely have the know how to do this, even before I asked, and the "skills" to really screw it up (why I asked! LOL)
Another option to minimize carbon issues on the threads would be to put in two cans of Techron Fuel Injector Cleaner about 500 miles before you will change the plugs. Techron does a great job of getting rid of carbon and the cleaning effect is dose dependent. Put the two cans in when you have half to 3/4 tank and will be doing a lot of around town short trips. The cleaning works best during heat up/cool down cycles rather than a long trip on the highway.
 
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