I need help. I don’t know Crap about engine performance mods. I have a IS300 I got couple months back. Bought it in spur of the moment deal without knowin much about it but I thought it was so sexy . From what I know now I would not of got it because the poor gas mileage I think caused from the the aftermarket mods specifically the cold air intake, the exhaust and I think its chipped too.

Someone told me there mods should improve gas mileage while someone else said the chip is programmed to throw more gas into engine decreasing mileage. Im thinkin those mods are hard on the engine that decrease the life of the engine and kill the gas mileage.

I get around 15 city and 17-19 highway and I only drive 60 on the highway. Everytime I drive over 60 I can feel the exhaust getting louder and the gas getting eatin up more . I was wondering what my options were to help my gas mileage and prolong the life of the engine. Should I take out all 3 or can I just replace one or two to help my gas mileage. Any advice or recommedations where I can take my ride for this type of work for cheap but good work. also considering replacing the cold air intake and exhaust back to stock.

Tank chu

imo i would just leave it as is, CAI should give you a couple more miles to your mpg. if you haven't already, get alignment done, check your air pressure.

THe car is rated at 16 city and 21 hwy so it sounds about right. Made sure you do a tune up if it hasn't been done already, check your air pressure like stated and you should get a couple more mpg.

gotta pay to play!

same for my SC bone stock 16mpg if i am lucky

thanks for the replies. What is the average rpms at 65. Mine goes over 3000rpms at that speed. is that due to the exhaust. i heard the avg at 65 hovers around 2600-2900 for that speed.

Also does having these mods increase the wear n tear on the engine

CAI should not have any negative impact on your MPGs from what I know.

What is that heat shield thing covering up your headers? That's kinda cool, never saw that before...

Yeah it's the Injen Cold Air kit with manifold heat shield. You don't see too many of them around.

yea maybe the MPG are caused by the cars need for tune up/ timing belt/ wires etc. see about doing your services and emissions service to see if those MPG go up.

it's actually 18/24.

No, just depends on how the owner treats the car.

On top of keeping your tires properly inflated...make sure you are caught up on your fluids....
tranny
differential
engine oil
coolant

Keep your air filter clean and try Seafoam to clean out the carbon build.

I have aftermarket intake, headers, ypipe and exhaust.....my mpg has not decreased. I avg 360 per tank.

You never seen this before??? lol

Probably a heat shield

Thanks guys. i keep up with maintanance. whatever is required at that mileage interval. i did the very expensive timing belt and pump at 90k. i do the regularly required oil changes. Have not done the air pressure yet for the tires on my 19s also alignment is off from a tow i had from a previous snowstorm. ill get my tire pressure checked , tires balanced and alignment this week hopefully my car will be smoother.

Sway is ur car chipped? Is a chip required to properly run these after market parts such as intake and exhuast? Im lookin to get my chip removed but i wondering if it will affect the performance of my air intake and exhuast. From what i heard the chip makes the engine work harder and throws more gas into it.

im goin to try that seafoam sway thanks for the advice