Poor gas mileage 1990 ls400 84k miles
06-01-10, 09:03 PM
#1
Driver School Candidate
Thread Starter
Join Date: Apr 2010
Location: florida
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Poor gas mileage 1990 ls400 84k miles
I've been putting lucas fuel treatment for the last 3 tank fills.
Changed spark plugs to iridium laser plugs and changed the intake air filter and the car gives me between 13.3 to 13.5mpg's all in city driving no highway yet. I'm thinking of also changing the fuel filter. Also when it's real hot and the engine has been idling for more then 10 minutes it's start to sputter and a kind of misfiring, i step on the gas pedal and it takes a couple seconds to clear the sputtering.... Help!!!!!!
And the speedometer and tach gauges slightly move, everything else works in the cluster. Help again!!!!
Changed spark plugs to iridium laser plugs and changed the intake air filter and the car gives me between 13.3 to 13.5mpg's all in city driving no highway yet. I'm thinking of also changing the fuel filter. Also when it's real hot and the engine has been idling for more then 10 minutes it's start to sputter and a kind of misfiring, i step on the gas pedal and it takes a couple seconds to clear the sputtering.... Help!!!!!!
And the speedometer and tach gauges slightly move, everything else works in the cluster. Help again!!!!
06-02-10, 02:34 PM
#3
Driver School Candidate
Thread Starter
Join Date: Apr 2010
Location: florida
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
so the iridium spark plugs could be one of the problems?
What about the speedometer and tach gauges that they bearly move, what could be the problem there?
06-03-10, 03:30 PM
#6
Driver School Candidate
Join Date: Dec 2009
Location: Oklahoma
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
My 95 kept throwing the CE light. Had it checked and it was the post cat O2 sensor(s). Had a friend (local Lexus technician) put in the O2 sensor bypass gizmos and viola! no more CE light. I said all this to say that recently I checked my milage from OKC to Wichita and got 23.5 mpg! Yes I know. I checked my math several times and it was accurate. BTW it has 283,000 miles and had new timing belt, caps, rotors installed at the same time as the O2 sensor bypass gizmos. Just gotta love that! When maintenance is kept up they are amazing cars.
06-03-10, 06:45 PM
#7
Driver School Candidate
Thread Starter
Join Date: Apr 2010
Location: florida
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Poor mileage
my 95 kept throwing the ce light. Had it checked and it was the post cat o2 sensor(s). Had a friend (local lexus technician) put in the o2 sensor bypass gizmos and viola! No more ce light. I said all this to say that recently i checked my milage from okc to wichita and got 23.5 mpg! Yes i know. I checked my math several times and it was accurate. Btw it has 283,000 miles and had new timing belt, caps, rotors installed at the same time as the o2 sensor bypass gizmos. Just gotta love that! When maintenance is kept up they are amazing cars.
Trending Topics
06-04-10, 12:15 AM
#10
I was **** before. I was getting like 360 miles per full tank. I don't have a heavy foot at ALL. My cousins all complain that I drive like a grandpa. I do now, because I am sick of the ******ing tickets and paying through the nose for tires, gas, brakes, and an old engine falling apart.
After replacing my main o2 sensors and my EGR vacuum modulator (which started throwing code 71 again), I am seeing 400-420 per full tank again. I do a lot more freeway driving though, so that's going to throw the numbers up a bit. And I do blast the AC.
I love speed but speed loves $$$. I love $$$ more than speed. That's my logic.
After replacing my main o2 sensors and my EGR vacuum modulator (which started throwing code 71 again), I am seeing 400-420 per full tank again. I do a lot more freeway driving though, so that's going to throw the numbers up a bit. And I do blast the AC.
I love speed but speed loves $$$. I love $$$ more than speed. That's my logic.
06-04-10, 01:53 PM
#15
Lexus Test Driver
Join Date: Jul 2004
Location: California
Posts: 861
Likes: 0
Received 0 Likes
on
0 Posts
whit ivory, so that is definitely not kilometers? If it is miles per tank, that is great. I wonder how much of a difference the octane makes in the mileage, like 91 v.s. 93. I know the couple times I put middle grade 89, the mileage sucked compared to the required premium.