Look I know nothing about the 4.7 engines, but as for the 5.9 I can speak volumes. I don't know how you could get 2-3 MPG more just adding a CAI. That just doesn't seem likely unless you simultaneously changed your driving style. When I did mine it got me and extra 0.5MPG, now to be fair I do not do many highway miles, but even still at most it gives me 1MPG more on the highway. To get that kind of MPG increase, at least from my experience, you need to upgrade the entire system (CAI,TB,Exhaust) to a more free flowing system. However, if your math tells you 2-3MPG just from a CAI then congrats.

 

My friend at the Dodge dealership printed out some TSB's for me that I've never seen before online. I'll try to find them and post them, or scan them and post them on here in the next couple days. It's hard sitting at the computer now that it's so nice out....

My Short and simple para-phrased version: The oil passages in the aluminum engine parts aren't big enough to properly circulate the engine oil. When the engine is good and hot, ie driving long distances, the oil in those passages begins to burn off, and over time, turns to sludge. Apparently the 4.7's, and whatever engine it was they used in the Concordes, have this issue. As a fix, they recommend changing oil between 3 -5 thousand miles. Synthetic may help. However, don't add any additives or cleaners, as this will dislodge any sludge and cause it to circulate around the engine, plugging up other parts. So basically what they are saying, is change the oil more frequently, and keep your fingers crossed. I'll post them on here soon. As for the yellow gunk inside the oil filler cap, change your PCV valve regularly, and use a paper towel to clean the gunk out of the filler tube, and wipe off the baffle in the tube. Because it's not a safety issue (I beg to differ when my engine siezes up at 70mph on the freeway) they won't recall / fix it. I'll post the TSB reports later today or tommorrow. Still want to read completely through them to make sure i'm not missing anything.

 

And again, I'm not saying don't buy a vehicle with the 4.7. These are pretty good matches for the Durangos. If I would have known all this before buying mine, I may have checked out the Tahoe a bit more. But my Durango is a good truck. Pretty much loved it from day one. But as in any vehicle, There are a few quirks to be aware of that may prevent hassle down the road.

 

Now today when I pulled in the driveway at my house. I notice the smoke by my front passenger's side tire. So I jacked it up and of course the wheel bearing went out!

 

Only problem I heard about on the 4.7 was the timing chain getting too worn out and loose. Both engines seem to have problems with overheating. My 99 5.9 and my fiances 03 4.7 run cool now with cooler thermostats.

 

Got the wheel bearing installed on this morning. Took it for a ride and now the front passenger's side where the wheel bearing went out now the caliper is locked so now have to replace brake pads for the front, turn the front rotors, and order a new caliper for the passenger's side front. It suppose to be here in the morning I hope. Hope it is only problem for now until I get enough money. Was going to use the money for spark plugs but it will have to wait now.

 

replace the rubber brake hose going to the caliper too, they tend to collapse internally w/o being 'bad' from the outside

 

Ok will do that too.