logancg89

Hey guys I'm still new to thee us forum. I've had my gs300 for about 6 months now, and I've done everything I can think of to try and improve the gas mileage. Its so bad going down the road you can smell the Unburnt fuel coming from the exhaust. And there has to be something I can do to get better gas mileage. My friend with a 93 sc400 gets better gas mileage than me and he dogs his car and I drive mine like a grandma. So any input would be greatly appreciated.

rapollon

iTrader: (4)

Check Engine light?

logancg89

no there isnt a CEL

TheMole

iTrader: (13)

What have you tried to improve the mpg? Might make it easier for everyone to narrow it down.

logancg89

I've done fuel filter and air filter. I've also done plugs, wires, cap, and rotor. I always run premium like it says, also I always leave the pwr switch in normal. I've run out of ideas and this 14 mpg is killing me when it not that fast.

GoFastTSI

iTrader: (1)

O2 sensors.

logancg89

nope ive replaced all of them right after i got the car. I found a vacuum leak, and fixed that today so im gonna see how that does. It still smells like its still running to rich.

Nixspeed

It may just be a bad cat. Your engine may be running fine now but may have clogged up the car previously and now causing the sulfur smell. Are you noticing poor mpg or just the smell?

logancg89

Yea just bad gas mileage but it passes emissions so if it has a bad car wouldn't it fail emissions?

guardrail9

how many miles on the car? mine did the same exact thing. until i did a full on fuel system cleaning, including cleaning up the throttlebody and running a induction cleaner through the brake booster vac line to the intake and a good treatment of fuel cleaner. also check timing...

Nixspeed

Yeah if it passes emissions it may just need cleaned out like he said. Lots of carbon build up in the intake area.

twojayzee

Have you done a compression and/or a leak down test ? That will tell you/us alot about the motor.

logancg89

Ok guys to start off sorry for the lack if posting its been crazy at work, and I've also had a lot of side work as well. But back to the topic it just turned over 270,000 miles. Haven't done a fuel system cleaning but i do run Lucas about every third tank of gas. I'm only running premium, also I found a giant Leak on the backside of the air intake tube. I plugged it and now in creeping on 19mpg which is better but I wish I was around 22mpg. And also I have not done a compression test or leak down test seeing as its so hard to get to the plugs. And j was always told to do a compression test on motor at operating temp.

guardrail9

Yes it needs to be warm. How's inside the throttle body and plate look after having a leak in the intake tube. Lucas is good because it cleans up the fuel delivery system but doesn't touch the induction phase. I recommend cleaning that next