solve the puzzel
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solve the puzzel
I have a '99 SD CC 4x4 5.4 auto. K&N filter. The puzzel has to do with milage. Three months ago I was getting 15 mpg on the hwy., 13 city. Two months ago it went to 13mpg hwy and city. It varies, 13.2-13.0. I cleaned the K&N filter, which seemed to make it more responsive but didn't improve the mpg. I recently had a cat back straight through muffler exhaust system installed. I heard that might help. On a trip of about 130 miles yesterday I was still getting 13 mpg. on the hwy. Am I expecting too much? I don't think so. I was getting 15.0 on the hwy. What should I be able to get ? It's really beginning to bug me. Something is wrong besides what's the matter. I need someone who's been there done that , to help me solve this puzzel. Thanks, God Bless, Huckster
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Joined: Jan 2002
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From: USA
solve the puzzel
Is this manual hubs or auto for 4whl?
Maybe the auto hubs aren't releashing ,get under
the truck and spin the axles to see if their free.
Have you cleaned the maf sensor lately,since your running a k/n the oil sometimes gets on the sensor .messes up the computer /air flow readings
also chk that 02 sensors are working and the computer isn't running in open loop mode
are you consistenly using same brand and octane gas? different fuel blends burn differently
Just a few things
Rich
Maybe the auto hubs aren't releashing ,get under
the truck and spin the axles to see if their free.
Have you cleaned the maf sensor lately,since your running a k/n the oil sometimes gets on the sensor .messes up the computer /air flow readings
also chk that 02 sensors are working and the computer isn't running in open loop mode
are you consistenly using same brand and octane gas? different fuel blends burn differently
Just a few things
Rich
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From: Broussard USA
solve the puzzel
I also dropped MPG over time. I have a V10 and am 2 MPG worse now that I used to be. I tried FI cleaner, new plugs, fule filter and air filter. All I did was spend money on something other than fuel. I have no idea whats up. I also went up on my tire PSI and that did not work. I had a check for codes and nothing there either??? If you find something let me know.
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Joined: Dec 2001
Posts: 149
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From: Ft.Lauderdale USA
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Did you un hook the battery?? after the new mods?? Unhook it for 30 min.
Computer needs to reset and relearn whats going on.
Then it takes 500 or so miles to relearn,
How fast do you drive??
twinbulls
Computer needs to reset and relearn whats going on.
Then it takes 500 or so miles to relearn,
How fast do you drive??
twinbulls
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solve the puzzel
Thanks for the ideas. tire pressure okay; same octane rating on the fuel; hwy speed 65-70; never heard of the computer reset thing, I'll try almost anything at this point; still need to clean the MAF sensor. Keep the ideas comming. I'll let you know if/when the puzzle is solved. God Bless, Huckster
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Huckster
WHAT method do you use to compute MPG? What state are you in?
Several things can cause this.
Different fuel is possible... same octane rating does not mean anything, but what brand does. Many of us have found that Chevron with techron is the most consistent blend from state to state and seems to yield the better performance and MPG.
Are you in a state that has some blended fuel requirement in the smog heavy summer months? These blended fuels kill mileage!
Fouled oxygen sensors can screw up MPG
Sticking Idle Air Control can screw up MPG
Slipping or non-working lock up portion of torque converter
Brake drag
4X4 front hub/s locked
Heavier than normal right foot
Contrary to new thinking, spark plugs can make dramatic power and mileage effects, same with wires. If yours are arcing, hardened and loose then get new wires. Use the factory plugs, they are best and cheapest... most of the high dollar heavily advertised "new" plugs are snake oil and don't do squat.
WHAT method do you use to compute MPG? What state are you in?
Several things can cause this.
Different fuel is possible... same octane rating does not mean anything, but what brand does. Many of us have found that Chevron with techron is the most consistent blend from state to state and seems to yield the better performance and MPG.
Are you in a state that has some blended fuel requirement in the smog heavy summer months? These blended fuels kill mileage!
Fouled oxygen sensors can screw up MPG
Sticking Idle Air Control can screw up MPG
Slipping or non-working lock up portion of torque converter
Brake drag
4X4 front hub/s locked
Heavier than normal right foot
Contrary to new thinking, spark plugs can make dramatic power and mileage effects, same with wires. If yours are arcing, hardened and loose then get new wires. Use the factory plugs, they are best and cheapest... most of the high dollar heavily advertised "new" plugs are snake oil and don't do squat.
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