I have Toyota Corolla 2003. It is using too much gas. What are the possible problems that need to be solved? Is it a problem in intake the manifold or in the exhaust system or something else?
Your first bet is to give it a tune up. That would involve changing the following items:
- Spark Plugs
- O2 Sensors (whether codes are present or not)
- Cleaning the Mass Air Flow (MAF) sensor
- Cleaning the upper intake tract (using a Seafoam treatment or the like)
- Reset the learning state of the Engine Control Module (ECM - computer). You do this by unplugging the battery for a half-hour or so, or while you are changing out the spark plugs. This will get the computer back to an initial state so it can learn the new spark plugs and O2 sensors instead of dumping fuel for the old ones.
Depending on the mileage, you'd probably want to consider having the timing belt change. This will not affect your mileage, per-se, but will allow your engine to continue functioning.
Worn out piston rings, or other issues causing low compression.
It might be that you need to change your spark plugs.