low mpg=problem?

[maximus]

So as i stated in another thread, my car has dropped a decent ammount of mpg in the past couple weeks. I just did an average at the pump and got something like 15.3 mpg. That is with short like 10 min drives to and from work where it is 50/50 highway-street. I dont think I have taken the tach above 3k accept to get onto the highway which it would have only seen up to 4k before a shift. Could there be like a vac leak or something dirty or anything that would cause me to get such crappy mpg? I don't know much about the mechanical part of our cars so any advice or ideas would be great.

[Kiljosh]

You can try resetting the computer so it will learn everything over again since the weather has started to change.

Clean the Mass Air sensor, run some fuel system cleaner through it, change to a lighter oil, check tire pressure. Air filter might be dirty from winter check that. Maybe the fuel filter clogged up.

No exhaust leaks?

Long shot is the car is running rich and burning through too much gas, cats are clogged up, o2 sensors failing(but with no CEL it's doubtful), bad gas.

Lots of stuff can cause bad gas mileage.

[maximus]

^ yea i know, just wondering if there was anything i could check w/o taking it somewhere to get someone to do a full on tune up on everything. Is there an easy way to check if I have an exchaust leak? I just checked the air filter last week and it was still decently clean. I have a chip and tune so I don't think it could be running rich. If its bad gas, ive been getting crappy gas for a while cuz ive been getting around 15-16 mpg for a couple weeks now. only have about 34k on it too.

[SpectorV]

short drives like that where the engine barely gets warm is probably the reason.