I can't understand how so many people her say they get such good gas mileage I have a 2000 4.7 Quad cab and I got 8.4 this week, I once added F.I. cleaner and added super unleaded and the best I got was 10.2 mpg,I have a flowmaster cat back which some say makes worse fuel mileage? I dont have a cai or any other mods,what can I llok for as a problem area for this poor mileage,plugs wires etc?I don't really have a heavy foot and I even tried going easier than normal and it always stays at 8.5 mpg?

 

You got some problems.....I get 13-14 in town and 17-18 on the highway.

 

It does sounds a little low. My milage seems to go down a couple mpg when it gets cold but I'm still getting 11ish in town and 17ish on the highway. It also helped when I checked the air pressure in my tires. I had new tires put on my truck when I got it and the mechanics shorted the the psi by about 7. After I corrected that it helped the milage.

 

Hmm.. that is low.
A few question to ask:
- Any mod's (lift, differant tires [and if so, what size versus the stock size; refer to the label on the driver door for OE tire size], performance mods, etc)
- Tire pressure
- When was the last time you had a tune-up, or at least looked at: plugs, wires, air filter, PCV equipment, etc?
- Any stored codes (turn key on-off-on-off-on ["on" does not mean start the motor] and look at the odometer or tripometer for codes to come up), and what are they?
- Driving habits, as well as type of driving? City, highway (and what speed, 60, 70.. 100 ) And if it makes any differance, if highway, is it shifting into overdrive?
- Do you let the engine idle a lot? Some people (including me) will go warm up their trucks, come back inside, and start doing something, and forget they left their truck on.
- Punk teenagers/others stealing gas?
- Fuel leak?
And the last question of your exam, which is the most important:
- Is this a Dodge product?

It could be that your oxygen sensor(s) are not operating properly. Sometimes they go bad and don't throw codes.

 

are you sure you are calulating the mileage correct. my 05 4.7 with aftermarket cams, throttle body, intake , exhaust, chip is getting 17/18 around town and 20/22 on the highway. and this is with a heavy foot.when was the last time the cat was checked out. might be clogged. as for the 2000 4.7 we have no wires. coil packs. all you need to do is unplug coil pack and remove spark plug and install spark plug. reinstall coil pack. also when was your pcm reset. if not try this remove neg battery cable for 20 min. then reinstall battery cable start and stop truck 3 times. on the thrid time leave truck running for 5 mins. then take it for a drive. reset your mileage counter and see if this helps. if not try changing out your o2 sensors. and check to see if all electrical connection are connected and hoses also

 

Definitely check the plugs as mentiioned above. I have a 2001 QC with 4.7L, auto, and 89,000mi. I changed the original plugs to a NKG IR and went up 1mpg from 13.7 to 14.7mpg in town. that plus swithcing to synthetic 5W-30 helped. And ditto on the sensors - mine went out with no warning light, and mileage went down to around 9.

 

I had the same problem with my 98 dakota but with the 3.9L. I had to do plugs, wires, cap, rotor, pcv, breather, o2 sensors, change to all synthetic oils in my diff, trans, and motor to see a gain from 10 mpg to now an 18 mpg. I am getting the superchip to see it go up even more. I have a cold air intake which helps too. Try just doing new plugs, and changing your oils to synthetics, check your air filter too, you can't deny that part of your engine, and idling kills gas mileage. All these darn stoplights just robs gas mileage. Also try disconnecting your high side pressure switch on your ac compressor so that doesn't kick on, although it's used to defrost your windows, just extra things that take power away and hurts gas mileage. Hopefully this helps- Justin

 

yeah my 2002 dakota sucks on gas....i fill it up every 3 days, and it takes 50 bucks each time. and i only drive it to school. oh and i also floor it EVERY chance i get