I have the SC400 V8 model that has the ETC power/norm switch for economy control...it works like it should but I drive on norm all the time hoping to get SOME kinda good gas mileage but I've noticed that I'm barely getting 11~12 MPG and it's costing me big...I'm sure that I should get at least around 20.

I also think I have a slight oil leak from a faulty piston ring since randomly when I start my car (not everytime) it shoots a huge cloud of blue smoke(from oil). Though even if the cloud shoots out when I start the car, the smoke doesnt persist once driving, or even while parked. Would fixing that and doing a slight tune up (plugs and wires) help my mileage at all? Thanks in advance.

 

It needs tune up. What year and mileage is your car? At least it needs new spark plugs and injector/MAF cleaning.

 

you don't want to touch the MAF sensor or you'll screw it up entirely. The MAF sensors are really sensitive so don't mess with it. Sounds like you really need to do a tune up in conjunction with cleaning out the intake manifold of soot. When I had my 90k service done, the intake manifold was covered in exhaust soot from the EGR, where i was getting 9mpg. Afterwards, I was back up to 18-20mpg. I would also leave ECT off as that's just to allow the transmission to upshift later/downshift quicker. In normal city driving, I find that I don't need to rev the V8 any higher than 2k rpm. If you're going higher than that in city driving.... well that may be part of the reason for bad gas mileage.

 

I'm going on 250k for miles and its a 93. Thats wussup lexant I'll try cleanin it out...though the engine is incredibly clean...well till the oil leak lol. would the piston ring issue affect the mileage? i figured it would since it might screw up the ratio in the chamber.

 

I know its a different engine but im getting about 24~25mpg on my 300 with 180,000mi on it. Defiantly get a tune up.

 

a ring issue would burn oil, creating creep into your combustion chamber, and thus recirc through the EGR, making your IM a sloppy disaster.

 

I didn't think about it recircing thru the EGR...the leak just appeared not even a month ago...I bet my throttle body's a mess. Thanks for the help.