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New Person with a couple Qs on a 2000 ls v8

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Posted by: packman60016

Hello all got a couple questions I recently got a 2000 lincoln ls and it says that it takes premium unleaded octa 91 but would it be alright to use regular unleaded? Also I keep getting only 10.6 miles a gallon any reason for that. Thanks for any help.

Posted by: tagliato22

i would say no the the gasoline grade question.

as for you mpg...examine your driving habits. do you floor the gas pedal every opportunity you have? among other things, a tune up may also help if it hasnt been done in a while.

Posted by: pektel

Definitely DO NOT run 89 or... god forbid... 87 in your car. The extra dimes at the pump are WAY less than fixing your engine after it starts knocking from using subpar fuel. I'm pretty sure it has to do with the higher compression in our engines.

Posted by: MDavis0424

The LS V8 is a high compression engine, and requires high octane fuel to avoid detonation.

Have you checked the mileage by filling the tank a couple of times, or just using the message center reading in the dash? The dash reading is not always accurate. Search the forum for mileage, there are several posts on what most people get based on mix of highway/city and driving style, but most V8's get between 14 and 19 mpg. 10.6 would be possible in bumper to bumper stop and go, but otherwise there is probably something wrong. Any number of things could cause it from a stuck emergency brake to bad ignition coils. Are you getting a check engine light?

Posted by: King03LS8

I NEVER use anything less than 91 octane in my LS.....there is a reason is says 91+ on the gas tank.

Posted by: T_Man

Quote:

Originally Posted by King03LS8

I NEVER use anything less than 91 octane in my LS.....there is a reason is says 91+ on the gas tank.

Yeah..... and that reason is..... 10.5 to 1 compression ratio!

Posted by: packman60016

Thanks for all the help but I bet the private seller put in regular unleaded instead of the premium im sure thats why I get less mpg but he said that he replaced all the coils and it check out fine. There are no check engine lights. And do you guys think I should maybe change the fuel filter maybe thats causing the problem?

Posted by: moneyUWM

yea that may be the problem. Along with a tune up and perhaps some new spark plugs...

I have a 01 LS8 and Im getting 22.3 about average and Id say I drive like 40% highway and the rest city here in Milwaukee..10.5 or w/e is pretty rediculous.

As far as the gas question....I ran 89 on my first fill-up thinking..."eh, what could happen..." and it just ran crappy. Engine seemed louder, so I threw in a octane booster and it went away within like 15 miles...Id say, replace the filter, fill up with top grade gas, and throw in an injector cleaner ...

Posted by: pwr2killayak

91+ buddy. in houston all we have is 93. what states have lower?

Posted by: nickandersonLS01

we have 93 also, the day I bought my car the numb nuts salesman put regular unleaded in my car and the check engine light/emissions light or whatever it is popped up within 5 minutes.... change your fuel filter I got an extra 3-4 mpg out of doing that, and its cheap, fast and easy.

I'm pretty sure you would know if the previous owner was running under 91 octane, how many miles did you say are on the car?

Posted by: b34nz

I always use 93

Posted by: King03LS8

91 here in Austin, you can find 93 at select gas stations....

Posted by: RequestingFlyBy

I wouldn't use anything below 91. I'm is SE PA and the Sunoco stations have 91 and the Wawa's now switched from 93 to 92. My dad has a benz that takes premium, but he will fill up premium and when he hits a half a tank, he will fill up with mid-grade to mix the two. Seems to work and he hasn't had any problems with 253,000 on the odometer. Has anyone tried this with an LS?

Posted by: Eliot_Ness_Ls

Quote:

I'm pretty sure you would know if the previous owner was running under 91 octane, how many miles did you say are on the car?

How so?

The idiots I bought my car from told me it takes lower grade, of course I never put anything lower than 93 from Sunoco in my car cause of the most simplest fact being it tells you so right on the damn gas door. I had poor MPG for a long time till I used that seafoam but I have this tapping/slight knocking coming from around my intake manifold. Kinda sounds like a old Volvo...lol.

Posted by: packman60016

Thanks again for all the help guys. but its a 2000 with 66,000 miles on it. I filled her up with 93 and its sounds great and now im getting around 16 mpg now and when I replace the fuel filter I bet even more. Again thanks all for the help

Posted by: vicls

Always use 91 octane i rather pay the extra cents then pay for a new engine

Posted by: 02lsv8sport

I have always run 89 in my 2002 V8 and it performs beautifully with 20-21 mpg mixed city and highway. I have had my car for over 4 years. I have got as high as 28 in all interstate driving.

I did try one tank full of 87 octane which performed o.k. with no knocking whatsoever, but just to be on the safe side I went back to 89. The people who can only use 91 or 93 octane must live in very hot climates. Although in the Atlanta area we have had 8 straight days of 100+ temperatures.

Posted by: gcwimmer

Out of the 2004 owner’s manual:

Octane recommendations

Your vehicle is designed to use
“Premium” unleaded gasoline with
an (R+M)/2 octane rating of 91 or
higher for optimum performance.
The use of gasolines with lower
octane ratings may degrade performance. We do not recommend the use
of gasolines labeled as “Premium” in high altitude areas that are sold
with octane ratings of less than 91.

Posted by: Jim Henderson

I bought my 2004 LSV8 used with almost 14,000 on it. I now have about 56,000 miles. I have had warranty issues with tranny from as soon as I bought it but didn't realize it and a bad fuel pump at about 35K?, wheel bearing at about 50K? and 7 of 8 coils after idling on a 105+ day for 90 minutes due to freeway closure. All fixed under warranty and in my opinion not related to fuel octane issues.

I do several full throttle rolling starts with the LS every day in my commute. My commute is about 10 miles stop and go in the afternoons, about 15 miles street no traffic and then about 35 miles of frfeeway speed between say 50 and 80 mph.

Octane required depends a lot on driving style, weather, quality of gas, condition of engine etc. Everyone's experience will be slightly different.

I change octanes maybe once a month just to fool around and I take notes in my log book. If you run 87 octane and have a heavy foot you WILL have pinging from light to moderate. With 89 which is what I run probably 80% of the time, you might get a light ping on heavy acceleration on a hot day. I never have had a problem with 91 which I run maybe 10% of the time, and since it is in the manual it is the safe bet.

Interestingly I seem to get best mileage with 89. If I run premium and then change to 89 or even 87, the mileage goes up a point or two for one tankfull. Could be coincidence. A steady diet of 87 or 91 gets me about 1mpg less than 89 according to the info panel.

Pinging can be worse in older cars that are out of tune or have carbon deposits in the chamber. The can also affect gas mileage, so your problems may be related.

I get about 17-19mpg on my commute as described above. I have seen as high as 25 on a long trip LA to Vegas at 80mph.

Things I would check is air filter, plugs, O2 sensors, EGR, Plugs and maybe coils. Coils are a common problem with our cars, but usually you will notice a stumble under light acceleration at just below freeway speed. If they are really bad you will not miss the stumble and it happens at more speeds even idle.

Good Luck,

Jim Henderson