BAAAAD Gas Mileage
#1
BAAAAD Gas Mileage
Hey Guys,
I just got my '01 SCrew Lariat with 119,000 miles on it (4.6 engine) back from the shop for a tune up. I had em put new platinum plugs in (replacing the original plugs), New Fuel Filter, cleaned the fuel injectors also, using a synthetic, not a full injector flush. But even after that i am still getting HORRIBLE gas mileage in the city, about 9 miles to the gallon. I got the truck used and the guy said he had kept up w/ all maintenece but had no records to show :-(. But i noticed the mileage problem immediately. It is starting to make me mad, especially w/ a fill-up of regular gas nearing $45 and i am just out of highschool, so i am poor. I just need any suggestions u guys may have to help me out. Thanks.
Also. . . i have read alot about iridium plugs. . . anyone have experience w/ those?
Trey
I just got my '01 SCrew Lariat with 119,000 miles on it (4.6 engine) back from the shop for a tune up. I had em put new platinum plugs in (replacing the original plugs), New Fuel Filter, cleaned the fuel injectors also, using a synthetic, not a full injector flush. But even after that i am still getting HORRIBLE gas mileage in the city, about 9 miles to the gallon. I got the truck used and the guy said he had kept up w/ all maintenece but had no records to show :-(. But i noticed the mileage problem immediately. It is starting to make me mad, especially w/ a fill-up of regular gas nearing $45 and i am just out of highschool, so i am poor. I just need any suggestions u guys may have to help me out. Thanks.
Also. . . i have read alot about iridium plugs. . . anyone have experience w/ those?
Trey
#2
Well you have a heavy truck with a small engine and probably lead foot (most young guys do). 9 mpg in the city sounds right. My 98 ext cab 4x4 gets something around that. The older the motor, the less power which means you gotta apply more throttle for speed. Also I'm sure you run your AC which drains power. Welcome to truck life. I ended up buying a cheap little honda to drive to work and around town and kept my truck for weekends and etc..
#3
#4
9 is not acceptable.
i have a shop truck, 97 5.4 in a f250 with 140,000 miles and in the city with my lead foot it gets 12 to 13.
my 2001 supercrew 5.4 , it has a vortech s/c and also gets 12 to 13 city. ( i put the iridium plugs in and my mpg is the same.)
on a recent trip pulling a 5000 camper with gear i got 7 mpg with overdrive off and running about 62 mph.
thing i would check (if the motor seem to be alright)
tires, alignment and possible brakes dragging.
i have a shop truck, 97 5.4 in a f250 with 140,000 miles and in the city with my lead foot it gets 12 to 13.
my 2001 supercrew 5.4 , it has a vortech s/c and also gets 12 to 13 city. ( i put the iridium plugs in and my mpg is the same.)
on a recent trip pulling a 5000 camper with gear i got 7 mpg with overdrive off and running about 62 mph.
thing i would check (if the motor seem to be alright)
tires, alignment and possible brakes dragging.
#5
#6
#7
Are the tires the stock size, or does it have larger tires and the odometer has not been corrected?
As mentioned, dirty air filter, bad alignment, dragging breaks will kill mileage.
Also, a bad tank of gas will do your mileage in. Try filling up at another station.
And in hot, humid weather your truck is going to run richer, plus you are likely to be blasting the AC.
Maybe the EGR is clogged and should be replaced. Also have seen some posts about the IAC needing cleaning.
IMO, a cold air intake and iridium plugs are not going to make much if any mileage improvement.
Good luck with it - 9mpg does seem awfully low.
As mentioned, dirty air filter, bad alignment, dragging breaks will kill mileage.
Also, a bad tank of gas will do your mileage in. Try filling up at another station.
And in hot, humid weather your truck is going to run richer, plus you are likely to be blasting the AC.
Maybe the EGR is clogged and should be replaced. Also have seen some posts about the IAC needing cleaning.
IMO, a cold air intake and iridium plugs are not going to make much if any mileage improvement.
Good luck with it - 9mpg does seem awfully low.
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#8
#10
Sounds like you are getting fuel with 10% ethanol alcohol added.
My '99 5.4L auto gets 8-14mpg driving with ethanol blend - When I get out-of-state non-ethanol I can get 16+mpg highway, usually with premium almost 18mpg highway driving (Missouri & points farther south gas)
Remember they use ethanol to raise octane so often the mid-grade gas will be alcohol blend. With the recent gas price boost I've seen out-of-state 89 octane blend cheaper then the 87 regular!
Minnesota has MANDATORY 10% ethanol, we are at the end of pipelines, zero petroleum reserves here and get all sorts of exotic blends that aren't worth squat. But if the Arabs turn off the taps we will still have *some* fuel resources available. I use only BP here, just recently switched from Mobil - better power & less vibration...
EDIT: Oh ya - Oxygenated gas for Urban areas, subtract 10-15% milage regardless of Ethanol or not..
My '99 5.4L auto gets 8-14mpg driving with ethanol blend - When I get out-of-state non-ethanol I can get 16+mpg highway, usually with premium almost 18mpg highway driving (Missouri & points farther south gas)
Remember they use ethanol to raise octane so often the mid-grade gas will be alcohol blend. With the recent gas price boost I've seen out-of-state 89 octane blend cheaper then the 87 regular!
Minnesota has MANDATORY 10% ethanol, we are at the end of pipelines, zero petroleum reserves here and get all sorts of exotic blends that aren't worth squat. But if the Arabs turn off the taps we will still have *some* fuel resources available. I use only BP here, just recently switched from Mobil - better power & less vibration...
EDIT: Oh ya - Oxygenated gas for Urban areas, subtract 10-15% milage regardless of Ethanol or not..
Last edited by Wabbiteer; 07-23-2004 at 01:49 AM.
#14
I have heard that from a few sources, specifically Haynes repair manuals for vehicles I have owned. I'd have to do some research to learn more specifically about why, but there are many web sites that can explain it better than I would. It affects the intake manifold vaccum.
Look at me for the first Google hit.
Look at me for the first Google hit.