LScowboyLS

get your gas from Costco or Sam's Club, they are usually by far the cheapest and that "spread" between 87 and 92 is only 21 cents!

peterls

^^^ What LScowboy says I had the opportunity to confirm myself, and anyone else can do it too (you need to do all this under identical driving and weather conditions):

1. Make sure you gas up at the SAME station, using the exact same pump #. This way you will know that "full" is always identical.

2. Write down your mileage every time, and how much gas it took to fillerup to "full". This gives you exact MPG, everything else is guesswork.

3. Now do the same with a few gas tanks of premium and few times with regular. Note that you spend more regular than premium and save absolutely no money, and even loose some as you loose more power than you save in dollars.

I already did all that and calculated that there was no savings at all- as a matter of fact, it was MORE expensive to run regular. But you are free to not let facts spoil a good story

I work with computers as my day job, partially I do programming and solve some complex issues daily, so troubleshooting is my forte and when you want to know what is going on exactly, there is no better way than to be **** to a "t".

jared5

Im going to do this this week finals are done so i actually have time to clean them! Thanks for all the tips ill let everyone know if that fixed the problem!

Finn

IMHO based on my own experiences when chasing automotive gremlins such as engine running badly you first need to make sure that the engine and related systems are in good working order ie. basic tune up and maintenance is often what is needed first:

- fresh fuel
- plugs
- ignition leads
- oil and filter
- air filter
- fuel filter
- distributor caps and rotors
- no error/fault codes
- no air leaks
- no clogged exhaust or catalysators
- engine reaches appropriate temperature
- working lambda sensor
etc.

I don't mean that one has to do all the above, just make sure that everything is up to spec. Many, many times the problem can be something basic like a clogged fuel filter (my -86 Corvette) or something like that.

jared5

Okay so quick update, it took a bit longer to get the codes read i guess norcal doesn't do free code reads at part stores.. so my car is throwing code P1354, i looked it up looks like the VVT System Malfunction.. on top of that cylinders 2,4,6,8 are miss firing.. im going to do a tune up at he end of this week lets hope its just the plugs that's needed.. shop that read the codes put a cleaner in the oil also, im on my way now to get it changed to see if it was a sludge problem.

LScowboyLS

search on cleaning the VVT system on here

OMAHA

The Engineers Say Not To Use A Octane Rating Lower Than 91 In Your Fuel......

LScowboyLS

even if it was OK with Toyota to use regular gas, it's still not smart, because with premium, the gas mileage is improved enough that it more than makes up for the cost difference (on my LS400, 11% better mileage vs. 7% price premium for 92 octane at Costco)

Finn

Guys,

what is the octane rating on that side of the pond for regular and premium gasoline?

Is the US octane rating Pump Octane Rating ie. PON?

python

iTrader: (4)

you do NOT get better mileage with premium gas! other wise u can just go buy octane boost in a bottle and get great mileage!

http://www.csmonitor.com/Business/In...as-saving-tips

https://mn.gov/commerce/weights-and-...ctaneFacts.pdf

http://www.consumerenergycenter.org/...s_premium.html

LScowboyLS

sorry, but on LS400 (and most any other car calling for Premium only) you get considerably better fuel mileage with premium gas, this has been verified with controlled meticulous fuel mileage measurements by myself and hundreds of other members here on Club Lexus, please do a search!

I pay ~7% more for 92 octane over 87 at Sam's Club or Costco, and my mileage with 92 runs about 11% higher, on average, than with 87 - and if octane boosters work, and they may, that would likely be even more pricey than just buying Premium in the first place!

if you understand how the ECU works along with the knock sensors and the way it retards the timing and makes other adjustments to try and run acceptably on lower octane without knock (aka ping aka detonation), it is easy to see why the fuel mileage is better with Premium - and if 87 were just fine, then Toyota would not specify PREMIUM FUEL ONLY

manufacturers don't like to specify premium fuel only, it runs up the cost of ownership figures, so if regular were fine, they sure wouldn't be specifying Premium

not to mention the performance difference in not having these drastic ECU timing and other adjustments to try and cope with 87/89 octane

this has been hashed out on Club Lexus long ago, and I thought it was common knowledge by now, if you doubt it, then measure your own mileage with a tank of each!

rick1987

iTrader: (1)

bingo.

Gasoline is a pretty good cleaner!

python

iTrader: (4)

My mom lives 650 miles away...i drive there once a year for the past 7 years in my ls 400..i have ran on 87 both ways...89 both ways...91 both ways..absolutely no difference in gas mileage! none...and i just disproved ur theory by tests that have been done solely for this reason

PureDrifter

iTrader: (10)

actually the threads you speak of didn't have a consensus at all, I would know.


Regardless, this isn't the place for a fuel vs. mpg discussion, no more talk of that in this thread.

jared5

Hey guys just wanted to update! I had my mechanic change the Oil Control valve and the car runs amazing! It seems that it was the problem the whole time. i feel like i have an extra 100 horsepower and no more rough idle! Thank you for everyone's help.