Gas Mileage on a 2001 Solara SLE

[iFarbs]

I have a 2001 Solara SLE with a V6. I got the car and it had an aftermarket TRD exhaust on it and an aftermarket INJEN cold air intake on it. My problem is that i'm getting really crappy mileage as in about 10 MPG in town, and 20 MPG on the highway. My friend recently bought a cold air intake for his car, 2007 Monte Carlo and his mpg increased about 5 mpg. Now I realize these are different cars and different air intakes but why would my MPG decrease from what the supposed 27 MPG. So if you guys could give me some advice on how to improve this. My oil was just changed like 200 miles ago and I don't drive like a crazy person. Any help would be appreciated

[Jason.MZW20]

Might be a good idea to change the air-fuel ratio sensors (they are NOT oxygen sensors on the 2001 V6).

But, for the most part, if it's cold out, you'll get pretty terrible gas mileage. The colder it is, the richer the engine runs.

So if you're getting 10MPG city and 20MPG hwy, you're averaging 15MPG then? Where are your calculations?

[iFarbs]

Well I had a full tank of gas, for the first half i drove only in town getting 80 miles on a half tank, and for the other half i put about 150 miles on it going out of town. So i figured it out as getting 10 and 20 so yes 15

[fenixus]

you can't really estimate your MPG based on what you are doing or it will be VERY rough...

try this. go to gas station and refill the tank with your favorite fuel grade and reset the trip meter.
drive around, e.g. city mostly or highway mostly depending on which one you want to check, for at least half the tank.
go to (best if the same) gas station again and refill same fuel grade.

check the trip meter and write down the miles traveled (and reset it for further MPG check) and the gas station receipt will tell you EXACTLY how much gallons of fuel you used.

divide miles by gallons and you have your MPG based on driving scenario.

[Solid_Koolaid]

I got a 99 Solara SLE V6...

Ok it can get crappy milage in town but 10MPG !!! What the hell, I'll never believe that is normal. Unless he's driving it like he stole it at every single traffic light he encounters, my average in-town MPG is 18 and I don't drive like a grandma, it's around 40F max in the day and I drive less than 1.5 mile to my work place so the car's never warmed up on those trips. (Highway MPG is anywhere between 24 and 28 at 70 to 75mph)

So...

No check engine light on ?

No gas smell ?

Car behaves well ? start, accel, cruising, ... ?

Don't invest on sensors before having a bit of an idea what it could be. A/F sensors are not cheap. But this could be it for sure.


EDIT : Agree with the previous post, have a sure mean of calculating mpg. guesstimates with the fuel gauge, forget it, I sometime start the car and the gauge show more fuel than I had when I shut it down. When I drive in a curve fast enough, I'll have like 3 gallons more shown and It will also take forever to get from full to 3/4, then rush toward 1/2 etc.

[fenixus]

if he drives short distance (<2 mile) trips when engine is always warming up in city driving than MPG around 13-16 is normal on V6... besides his MPG calculations are way off because they are based on fuel gauge pointer which is not linear and pretty much inaccurate.

[Solid_Koolaid]

Originally Posted by fenixus

besides his MPG calculations are way off because they are based on fuel gauge pointer which is not linear and pretty much inaccurate.

Which I agreed upon in my edit

[fenixus]

Originally Posted by Solid_Koolaid

Which I agreed upon in my edit

just noticed the edit

[fenixus]

just to let you know and to cheer OP up

just refiled tank (89 shell fuel) in my '02 solara sle and got the worst MPG ever hehe

city driving only, and ONLY short distance on that tank, <2 miles trips and less <10-15 mins, engine never fully warmed up, current ambient temps in morning & evening @ 30F ... and the MPG is 11.53

perhaps I've got minor issues heavily impacting MPG in my scenario, like old thermostat (really slow warm up now in Winter), leaking PCV valve grommet (oil residue around it), possibly slightly dragging Front Driver caliper (anchor pins were stuck once, might did it again), my front struts need to be replaced and I have 1 loose strut mounting nut on Front passenger side... all of those minor things add up I guess.

[Mister_Perkins]

You should also keep the factor that its taking longer for your car to run at normal operating temperature now that its getting colder out too, so the IAC is going to keep the car running at higher RPMS since it takes longer. Plus its running more rich for a longer period of time when you first start it up.

[pmesfun]

My high school is about a 1/4 mile down the street, and all I do is city driving. I get pretty good gas mileage, right now I am at 320 miles with a 1/4 tank left. Try some fuel injector cleaner and see if that helps.

[fenixus]

Originally Posted by pmesfun

My high school is about a 1/4 mile down the street, and all I do is city driving. I get pretty good gas mileage, right now I am at 320 miles with a 1/4 tank left. Try some fuel injector cleaner and see if that helps.

Originally Posted by Mister_Perkins

You should also keep the factor that its taking longer for your car to run at normal operating temperature now that its getting colder out too, so the IAC is going to keep the car running at higher RPMS since it takes longer. Plus its running more rich for a longer period of time when you first start it up.

tried Chevron techron (both fuel and bottle concentrate) and tried CRC emissions formula cleaner too. thing is that I'm not convinced at all it's the dirty fuel system, because I would see high positive fuel trims in obd2 if that was the case. however the fuel trims on this car are almost perfect, meaning the Air Fuel Ratio is close to perfect, staying usually in ideal +/-3% range (when warmed up of course which never happens in my current driving conditions).

planning to sea foam it after Winter and fix mentioned above issues - i think the worst problem is the thermostat in my case. it really prolongs warm up phase, so when I park the car after 2 miles/10mins it's still not fully warmed up (almost, but not there yet) ... so i'm driving it basically all the time during warm up.

on a side note, IAC returns idle speed to almost normal (only slightly higher than normal 700) idle around 155F coolant temperature and the longest time it takes to get from 155 to 185F.

especially now when I use the heating at full blast from moment of engine start to keep my ass from freezing off (gotta love leather seats in Winter).

I recently compared warm up time to my 5s-fe with new OEM thermostat and that other car warms up after driving literally a quarter mile, while my 1mz-fe (with old thermo) cannot reach normal operating temperature in 2 miles of slow city traffic.

I was even thinking the thermostat could be stuck open, but then I found out that there is actually a trouble code on gen4 (since 2000 i think) to detect thermostat failure ... maybe detection mechanism sucks ... because this thermostat is obviously not reacting up to specs.

[pmesfun]

Hmmm...I'm suspecting the thermostat is causing your MPG to be low. That was my problem, but still you still should be getting better numbers. I was still getting around 350-380 a tank with the thermostat problem. Have you cleaned the throttle body and iac valve yet?

[fenixus]

thanks for ideas.

and no I haven't touched the TB&IAC yet on that car. I left all minor maintenance until Spring (had serious repairs going on in end of Summer then was finishing work on 5s-fe and then got lazy hehe).

now is kinda too late for anything (not a lucky garage owner am I), as we have the first snow here (flurry) and temperature is damn cold, especially with strong ice cold winds. besides days are too short to do anything serious (another disadvantage of being a shade tree mechanic haha)... I doubt I will touch it until after Winter.

as a band aid I will try waking up 10-15 mins earlier and giving car more time to warm up in a parking lot before taking it for a drive. I believe the thermostat on this car is not really stuck, but rather it opens fully too early (at too low temperature).

funny how a bunch of small minor things can ruin MPG and double the cost of fuel in the end result

UPDATE:
letting car warm up a bit for 5-10 mins in a parking lot prior to driving helps. it reaches full operating temperature in the middle of 2-mile trip now ... still long time to my taste, but hey it's better.

[mr1114]

I am a new Solara SLE owner. In town, stop and go driving, I am in the low 20s with A/C mostly off (did the calculation as described in post #4). Yesterday the tank was at the halfway mark at 180 miles.

I also warm the car up for about 5 minutes every morning before taking off.