bullboy85

ok guys im really running out of ideas now, had a fuel leak fixed that with a FASS so i have a really good LP and no leak. im haveing to run my tires at 45psi to make them last long enoff so i can afford new ones so i know thats an issue, but im still only getting about 12mpg. new intake on the way and just got a XZT+ running it on max milage so dont have numbers with them yet but still shouldnt i be doing better then 12mpg???

my02CTD

You will wear your tires out quicker running them low than if you keep them aired up to 65 lbs! That low of pressure will really bite the mileage bad!Dont hit the happy button too hard. Stay around 60mph. If you have any accessories like a bug shield, sun visor, or anything like that , they will cut into the mpg. Losing mpg's is a sign your VP may be having a slow death. Big tires will kill mileage. If its 4x4 with 4:10's it will hurt too. Just speaking from experience here . I got mine back to 19 to 20 .

bullboy85

no big tires, and with the tires fully inflated to 65 the middle of the tire wears really really fast and the outside not at all. 45psi evens them out... not happy about the cheep tires that came on my truck. im keeping the speedo at 70 or less, not stomping on the happy button, no accessories like that. really was hoping its not the VP but deff know thats a posibility cuz of the fuel leak made a loss in preshur which is really bad for the VP's dont know what gears i have... couldnt find anything to tell me. that 19 to 20 mark would be great just havent got there yet

Clunk

My fuel mileage gets better at 62mph or less....gives me an extra 5 minutes driving time going to work since my joyriding has been curtailed due to high fuel prices.

mhenon

You might check your MAP and IAT sensors. If one or both is off very much your mileage will suffer. Try pulling them first as they might just need cleaning. Have you checked for codes?
Mike

Valv

I agree with mhenon, check your IAT sensor, take it out and clean it well with carb cleaner. You might consider replacing it, it doesn't cost much.

Check your glovebox, there should be a label inside with all the accessories list and also the rear ratio, or check the differentials they should have a tag with ratio stamped on it and attached to one of the cover bolts.

In any case, even with a 4:10 your mileage is way off. There's something wrong .
Check rear brakes for dragging or sticking, clean IAT, pull any code.

I had a 1999 with 4:10 and I was getting 16/17mpg, and 12mpg only when towing really heavy and fast, and it was a 4x4 also.

mopar-or-no-car

The last tires I had on my truck I had aired up to 65 and they wore really quickly, then I aired them down to about 50-55 and they didn't wear out nearly as guickly at that pressure. I have 4:10's and generally get 19 imperial mpg's wich I believe is around 15 us mpg's. The xzt should help I think, allthough I put the edge ez on mine add my mileage didnt really seek to change.

Sunir

What is IAT sensor? Where are the IAT and MAP sensors located and how to check/clean them? thanks

mhenon

There both behind the fuel filter and a PITA to get at. The first one you'll find is the MAP (manifold air pressure?...boost) sensor and the the IAT (inlet air temp) is right behind it. I forget the socket size but they're big.
The electrical connector has a locking tab, which you can't see, and it needs to be pulled (straight down I believe) before the connector will come off. Look at one of the other connectors with this red tab and you'll see how it works. Pretty easy really.
Mike

mhenon

You need to pull the connector and get the right size socket and they'll screw right out. Use a 1/2" drive with exstention and swivel to get at the plugs. They're really tucked in behind the fuel filter so check it out with a mirror first.
Mike

Tocapet

The first one is 1 1/4" deep socket the back one is 13/16 deep socket, IF I remember correctly.

Sunir

I don't have the factory fuel filter anymore...my FASS goes directly to the VP....will this make it much easier to do? So once these sensors are removed how are they cleaned...with any special product?

bullboy85

carb cleaner and u only need to clean the IAT, i replaced mine, whats the easyest way to check the rear breaks for draging or sticking? jack up the rear and spin the tires? it seems like i should have a little more power going up hills then i do too. maybe im expecting to much as far as power but it seemed like my truck was really working going up a 7% gread last night not towing or hauling.

mhenon

Much easier! You should actually be able to see them with the OEM filter gone.
Mike

Valv

How about intercooler boots cracked,or partially disconnected ?