stupid check engine light

Slacker

New member
hello all! so I have a 04 sti and I have replaced both upstream and downstream o2 sensors. check engine light keeps coming on. the code is for a loose gas cap "p0457" its not loose...its new. also Is it normal to drive 145 miles and use three quarters of a tank of gas. im thinking not.. any ideas?
 

Spamby

Meat Product Toy
hello all! so I have a 04 sti and I have replaced both upstream and downstream o2 sensors. check engine light keeps coming on. the code is for a loose gas cap "p0457" its not loose...its new. also Is it normal to drive 145 miles and use three quarters of a tank of gas. im thinking not.. any ideas?

Any mods to the car? Do you have the capability to datalog?
 

IGOTASTi

System Operator
Staff member
What intake?
 

Slacker

New member
it is a K/n typhoon. it was on the car when i bought it a yeah ago. I might have just found the issue tho. right below and just left of the alt is a vaccume hose that is off. blue t connection. will keep you posted on that one.
 

HolyCrapItsFast

Drinks beer!
it is a K/n typhoon. it was on the car when i bought it a yeah ago. I might have just found the issue tho. right below and just left of the alt is a vaccume hose that is off. blue t connection. will keep you posted on that one.


I think that is it... I believe that connects to a solenoid near by and is related to the evap system. You may need to secure it with a wire tie
 

Slacker

New member
well the check engine light is off so far.. would that evap line mess with fuel milage. I have been tracking it and i at about 18 to 20mpg.
 

HolyCrapItsFast

Drinks beer!
That sounds like normal mileage for an STI around town. You should get between 24 and 27 highway
 

Alin

On a quest of STi erudition!

Slacker

New member
That e vap line seemed to have done the trick. my sti only has a typhoon intake, the rest is stock. now im getting 24 freeway and about 18 city.
 
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