the autolite 3923's are the best plug for the 3.9/5.2/5.9 motors, what do you all use in the 4.7? Im thinking I might swap them this weekend.

 

i was told the same works for the 4.7... Never tried it in mine!

 

yeah someone in the 3rd gen ram forum also said they are the ones to get for the 4.7

 

I have 4.7 4x4 2004 I just replaced plugs(plats by Bosch) at 96,000 miles. I thought the upgraded plug would be good. The truck runs ok but I think I probably lost 1 to 3 mpg. Wish I had read the site before... Maybe this will help others.

 

it's been my experience to ask 1st, then ask again and go with the majority... 99% of the time it works out good. Bosch plugs have never performed well in the magnum motors for some reason.

 

I have the Autolite 3923's in mine and they work great.

 

just curious here... what kind of mileage are you getting with your truck? my setup is very similar to yours except the K&N is still in the box in the garage and mines a 4x4

edit: forgot to mention that I get 16 mpg hiway driving like an old man...

 

I just filled up today and got 13.9 on my last tank with 85% city / 15% interstate. Of course we're going to have a high temp. today of 26 degrees so that doesn't help alot.
The best I've ever gotten was 17 and that was on the way home from buying the sucker. My tires ( Cooper Discoverer H/T 255 65 R16 ) have a max. pressure of 35 so that kind of sucks. I wanted to run them a little higher to see if that would help.
I am going to get a Flowmaster 40 Delta series soon and see if that helps a little.

 

yesterday I changed the oil in the 4.7 and found sludge @ the oil fill neck. I assume this crap is on the inside as well so I added a quart of MMO to clean it out. the sad part was I had mobil 1 15w-50 to dump in. so now it looks like in a couple of weeks to a month I'll be doing another oil change. hopefully that crap that is in there is hurting mileage and the MMO cleaning it out will bring some of it back. Others claim to get upper teens, low twenties for hiway mileage. If I could get that, I could be convinced to park the diesel for the $ savings when you compare the two. I will post back in the forum once I know what the deal is.

edit: forgot to mention... my daughter had great sucess with mmo in her honda motor... she went from mid 20's to low 30's on the hiway... obviously I dont expect that much of an improvement but If I can get more into the upper teens, i'd be happy.

 

So, my word isnt enough? In my 3.7 which is the same motor with 2 cylinders chopped off, I put the 3923's in and it made a HUGE improvement to the idle and throttle response. Also made the truck run much smoother.