MPG Issues

[2001MagnumPower]

Hi, my name is Tim and I have a 2001 Ram 1500 Ext Cab SWB with 5.2 L and 5 speed, I cannot seem to get above 10 to 12 miles to the gallon and its 2 wd. Not sure wat Im doing wrong, my 82 D150 with big jets in the carb and a heavy foot got better than this. I am open to suggestions....

[nhdriver]

Did your old D150 get that mileage w/ 10% ethanol crap they sell in most states now or with real 100% gasoline? you can lose 4-5 mpg with the lousy fuel they sell now.

[JVMopar]

Oh good god here we go with blaming ethanol again.

You should be able to get better than that. So start with the simple things first. Tune up, air filter, tire pressures, etc. If it's all up to par then it's time to look at the scan tool data. Things like coolant temperature, air temp If this all looks ok and it's getting up to temperature, then you have to start looking at your right foot.

I get over 20mpg with my '90 W150 318 4spd.

[2001MagnumPower]

Yes my old D150 used the ethanol blende fuel it was just 7 months ago i was driving it. And i cannot figure out it has a code flashing up about emissions system large vacuum leak and small vacuum leak but i was told by the so called shop that it would not affect anything and against my better judgement i took there word for it.

[nhdriver]

Get another opinion.

[cageman]

or do math better on the old one.

[2001MagnumPower]

I have changed filter it has a CGS cold air intake with a 65mm ported and polished throttle body, with a terminal velocity power chip, and none of these seem to help the poor fuel economy even running fuel cleaner and 93 octane...

[fox]

I'd start by checking the intake pan gasket for leakage.
do this.
Remove the oil fill cap and place a piece of paper over the hole. With the motor running, the paper should lift off. If it sucks in, the gasket is leaking.
Clean the throttle body of soot too.
Check the plug wires. Does it idle good?

I built a 402 for my durango with 9.5 compression and a 4 bbl intake, using the factory injection and TB. Then some fine tuning.
I can get 16 everyday driving and 19 or so highway at 65-70.
i'd like to change gears to 3.21 or 2.94? To slow it down more.

[Dick]

It could also be your cat is starting to plug up, in which case, the exhaust is stifled and it will take more throttle to achieve any given level of performance.

How is your oil consumption? If it uses oil, that is a sign of the plenum gasket being blown, as was referenced before and that oil being sucked in and burned is what can clog up a cat.

[talon6]

holy crap, a 65mm tb. that cannt be helping anything. i know guys that have built motors and blowers that arent running that big of a tb. 50mm is about right.

and its probably a blown plenum gasket. but these motors just donnt get very good fuel economy.

[nhdriver]

Originally Posted by JVMopar

Oh good god here we go with blaming ethanol again.

You should be able to get better than that. So start with the simple things first. Tune up, air filter, tire pressures, etc. If it's all up to par then it's time to look at the scan tool data. Things like coolant temperature, air temp If this all looks ok and it's getting up to temperature, then you have to start looking at your right foot.

I get over 20mpg with my '90 W150 318 4spd.

Do you dispute the fact that the 10% ethanol fuel sold in most states hurts your fuel mileage over 100% gasoline? I did my own test in my '03 PT Cruiser on a trip I got 23 mpg w/ the 10 % & over 26 w/ 100% gasoline.