Poor gas mileage?

MDLSV8

MDLSV8

LVC Member
Joined
Nov 15, 2004
Messages
37
Reaction score
0
Location
Upper Marlboro, MD
Filled up the tank 2 days ago. Almost empty already and have only driven like 90 something miles. I noticed that for every 1 mile on the odometer, I lose 2 miles on the "Miles to Empty" gauge. Any ideas guys?
 
Obvious: Gas leak
Not so Obvious: 02 sensors making car run super rich.
Or: Left foot on brake while right foot is on gas.
icon12.gif
.
 
I don't see any puddles under the car. I normally use the hightest 93 octane, but they were out so I filled it up with 89 octane the mid grade. What can I do?




MonsterMark said:
Obvious: Gas leak
Not so Obvious: 02 sensors making car run super rich.
Or: Left foot on brake while right foot is on gas.
icon12.gif
.
Click to expand...
 
MonsterMark said:
Obvious: Gas leak
Not so Obvious: 02 sensors making car run super rich.
Or: Left foot on brake while right foot is on gas.
icon12.gif
.
Click to expand...

could have a sticky caliper. My right rear was sticking several years ago... the Lincoln shop identified the problem while the car was in for another issue.
 
eL eS said:
could have a sticky caliper. My right rear was sticking several years ago... the Lincoln shop identified the problem while the car was in for another issue.
Click to expand...

I suggest starting up ur car...get out and go to the back of it...
if u happen to see thick black smoke alot, then it's definitely running too rich(using more gas than air).
put ur hand in the path of the exhaust, not too close, if u get some black stuff on ur hands..definitely too rich.
ttyl and good luck!
 
89 Octane in 1 tank shouldn't make much difference. Using 87 will. I know I tried it. Also mabey your computer is wacked. Try filling it, then drive a steady 50 miles on the highway and refill. Check mileage and see if its accurate to what your car is reading. It should be real close. My battery was dieing one time and that also screwed up the computer. All kinds of stuff was erasing. Mileage whacked out, and things like that. Check your battery also. Make sure it has 12.8-13.1 volts with the car off. Good luck.
 
bad move using anything less that 91+

your could try disconnecting the battery for 10mins - that should 'reset' everything and start the calibration over.
 
Quik LS said:
bad move using anything less that 91+
Click to expand...

I agree...with the amount of compression that this engine has you're taking a serious risk of damaging the engine. Even one tank of the "cheap stuff" is a risk.
 
MDLSV8 said:
Filled up the tank 2 days ago. Almost empty already and have only driven like 90 something miles. I noticed that for every 1 mile on the odometer, I lose 2 miles on the "Miles to Empty" gauge. Any ideas guys?
Click to expand...
I just got my LS today and the computer said it is averaging 9 MPG!!!! :Bang

I hope that is worng cause that would suck!!!!!!!


BTW, this is my first post and I just wanted to say hi to you all!!!!!!!! :Beer

Donny
 
Most likely they had the battery disconnected - so the fuel computer doesn't have enough time under it to make a good call on the mileage.

I have this same problem as I disconnect my airbags when racing on the weekends, which means I disconnect my battery. Once I reconnect I run around with single digit mileage for a while.
 
what abotu replacing the fuel filter??? could that help gas mileage? just a thought
 
Low Octane Gas

Just to straighten the record here, one or two tanks of low octane gas will not damage the engine in the Lincolns. There are knock sensors that will adjust the engine timing to ensure that the engine will not elf destruct. It will however have a drastic effect on the performance of the car and also on the fuel mileage. I do not believe that there is anyone on this board with definitive proof that a properly functioning engine of any make was "destroyed" or even damaged by using a few tanks of lower octane fuel. With the advent of knock sensors and computers, engine "melt downs" are a thing of the past.
 
vacuum leak???? bad maf???? extremely dirty air fiter???? under-inflated tires????
 
I have 2004 V-6 and have never run anything but 89 and have not had a problem. The computer will detect knock and back the timing off (retard). This car runs great.
 
That's a good thing becuase before i even noticed on the fuel door it says 93+ i filled with the mid grade stuff. I was scared i might have messed something up.
 
bufordtpisser said:
Just to straighten the record here, one or two tanks of low octane gas will not damage the engine in the Lincolns. There are knock sensors that will adjust the engine timing to ensure that the engine will not elf destruct. It will however have a drastic effect on the performance of the car and also on the fuel mileage. I do not believe that there is anyone on this board with definitive proof that a properly functioning engine of any make was "destroyed" or even damaged by using a few tanks of lower octane fuel. With the advent of knock sensors and computers, engine "melt downs" are a thing of the past.
Click to expand...

I'm sorry Buford...but I can give you many instances of severe damage caused by detonation...on late model vehicles. But not with an LS. That one I have yet to see. You are correct that is shouldn't happen with a perfect factory tune, but we all know that is a "myth" in many circumstances...i.e. when you deviate from the factory minimum fuel requirements, you are no longer in their factory tune. You need to remember that detonation on these cars will cause the knock sensors to pull timing. But if it's bad enough, the software can't pull enough timing out and you still get it. And remember...you can't always here detonation. Sometimes it's so slight that it's not readily noticable to the naked ear. I remember once filling my wife's Aviator up while we were on a trip. We were at 7000 feet elevation when we filled the tank and the best we could find was 87 octane. We dropped down in elevation to near sea level and high heat...with the a/c on. The thing pinged like crazy. We had to turn the a/c off and it still pinged. The computer just couldn't pull enough timing for the swill we had to run. Once we filled it back up with 91 octane, we were fine.

So yes...one tank of poor gas could cause engine damage...especially with hard driving and heat.

By the way...03 and 04 Cobra's don't even have knock sensors...even with a supercharger. The wrong fuel will kill those engines in a heartbeat.
 
Agree, Mostly

While I agree for the most part with the last few posts, modern automobiles are built with a certain amount of idiot proofing built in. If you want to throw in such variables such as an idiot driver, high temps, altitude, then no, not one auto maker can build a complete idiot proof car. But in all my years as a mechanic, i never saw one car that was driven reasonably driven with low octane fuel destroyed. That is the same thing as a car that has a redline on a tach, but no rev limiter. Somewhere, sometime, some idiot will take that car over the redline and cry when they grenade the engine. I stick by my claim that one tank of low octane fuel will not destroy an engine, with the clarifying remark that the car can not be beat or subject to harsher than normal conditions. Hell, I see people filling cobras and ls6 corvetts with low octane regular all of the time at my favorite filling station. Week after week after week. And their cars are still running. Of course they are always in the slow lane letting me pass with my high octane drinking Mark VIII. But it does seem as if we are all in agreement that if you beat it, feed it.
 
You must log in or register to reply here.

Members online

No members online now.
Total: 149 (members: 0, guests: 149)
Back
Top