Engine What factors can cause poor gas mileage?

What factors can cause poor gas mileage?

Hi, I had a previous thread about poor gas mileage and now I'm even more dumbfounded. I've put back on my stock airbox with a new filter in my 95DX with 72K miles, but am still getting around 18MPG in pure city driving. I don't drive aggressively, the car's maintenance have been kept as specified by the manual. I even had a new PCV valve put in a thousand mile ago for kicks and giggles. What can be causing such poor MPG in a Corolla? My daily driving consists of driving 3 miles from home to school, then back, and usually repeat twice thereafter. So on average, I do 9-12 miles per day with 4-5 stoplights per each trip. I would really appreciate any help, or is my car just getting old?

try adding some fuel injector cleaners, see if that helps. Are you in a bad traffic area? cause that can cause it if you do alot of stop and go.

You're not driving far enough. Short trips are hard on an engine. Your engine is probably just getting up to optimal operating conditions and you shut her down. This also causes hot soak on the injectors. This could be only part of the problem, but it's a start. Try doing a Seafoam and Deep Creep treatment.

Fuel filter was 5 months ago, or 3,000 miles ago. Tire pressure is around 35PSI cold. Distrivutor cap with spark plugs, and wires changed at 60,000 miles, which was probably 3 years ago. Rotors and pads changed about 1.5 years ago. <br />
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Just curious, what does the rotor have to do with gas mileage?

check if your brake is seized up or something, the stupid 3 speed automatic i dunno y but toyota hav to put a 3 speed auto, needs more driving cuz driving short distance can cause build ups in valves and stuff other than that what ppl above said...

Rather than short trips being hard on the engine (which they are), you also have to remember that the ECU feeds more fuel to the engine for cold driveability and faster warm-up. Engines consume considerably more fuel until they are warmed up (it is in open-loop and completely ignores the O2 sensor until coolant reaches like 150ºF).

If I were you, I would make it a point to take the car out on the highway and do some easy highway driving (like 2 hrs or more of driving 60-70mph) to see what kind of fuel mileage you are getting. IF the car is still capable of achieving high fuel mileage on the highway, then that pretty much rules out any kind of mechanical problem.

Injector cleaner is certainly not a bad idea - Seafoam works wonders.

Trav

What does this mean and how can I check? Thanks

I have noticed that when I brake hard...say form 40MPH to 5MPH, and let off the brake, my car would be in "neutral" (no movement) for a second, followed by a small clunk sound and a lurge forward and then I can accelerate again. Is this because my brakes are seizing up? Or because my tranny is dying.

I actually have great highway MPG! And have used Seafoam a month ago, I will go get some fuel injector cleaner, any recommendations? Thanks

what is seafoam??