94 corolla horrible gas milage, HELP

1994 Toyota Corolla 1.8liter Auto 98k

I realy like this car but I will have to get rid of it soon if this continues. I fill the tank, and I recorded how many miles per the whole tank i get. With out going over 3000rpms and usualy staying below 2500rpms once I got about 183miles for the whole tank. I only have 98k on the car and its an auto 1.8liter. I have replace many things that could help

- Feul Filter
- Distributer
- Ignition Rotor
- Spark plug wires
- Performance intake filter
- changed oil
- Changed transmission fluid

I use this car for deliveries so it is essential I get good gas milage thats why i bought this car. The thing looks mint condition, the A/C works, tranny shift perfect, Engine looks immaculate just the horrible gas milage needs to be solved. I cant figure out why!

__________________

-if you havent, buy chevron techron fuel additive to clean out your system if its dirty, that is killing mileage.

-also clean your maf sensor [if you have one on that model] with throttle body spray. if its dirty its telling the motor to inject too much gas.

-if youre using 87 octane gas try 89 octane after the system is cleaned.

-if you bought cheap plugs that could be causing it, I'd get stock plugs or ngk plugs.

-use synthetic oil if youre not. if your oil is normally dirty when you change it then start changing it sooner since dirty oil causes more friction and less mileage.

-if you have low tires air them up and that will help. if you have big thick wheels on it that could rob mileage.

-check for dragging brakes, bad alignment, steering wheel vibration from bad tires or warped rotors/drums. this could all be making the car fight harder to get down the road.

Do you have a hole in the gas tank? Dirty air filter? Or a siphoning neighbor?

Something isn't right, because we get 325 with the 1.8L. Good on gas but it leaks oil

im gonna get some NGK plugs and borrow my friends brand new K+N filter thnks for your help

also check your fuel line for any leaks. if you've made sure its from nothing listed above mechanically, and you leave your car outside where others can get to it then buy a keylock gas cap and see if the mileage improves then. if so you'll know you had someone sucking your gas out.

I concur with everything the guys up top said, with only a few additions..but important ones:

Try a set of NGK V-Power spark plugs gapped at .045..I use these plugs in my 86 prelude Si and I love em..they are only about a buck fifty a piece.

If you can afford it, go with Royal Purple 10 w 30 synthetic engine oil..it's quite steep per quart but well worth it.

But..you know, from everything you said that you replaced on it, and the age of the car..you shouldn't be having any problems at this point, which leads me to believe that for some reason your engine has suffered major trauma..either the rings are bad and you have low compression, or your valves are worn and not seating properly in the head, allowing fuel to pour through around the valves.

How about your exhaust system? Catalytic converter and muffler in good condition?

It could be the tires under aired, as someone already mentioned, clogged injectors possibly..I no nothing about MAF's so I can't speak on that..

I suggest that you have an engine diagnostic performed by a reputable repair center and find out what's going on inside your engine, and work from there.

Good luck :)

Greg

All good advice.

I would like to add it could be a leaky injector... I beleive a fuel pressure test tapped into the fuel line could detect this. Something a mechanic should do if you don't have the tools or aren't very confortable doing the work yourself... if you do do anything, remember the fuel ines are under a lot of pressure. The pressure should be relieved before doing any work on the car.

Also make sure you don't run too heavy an oil weight for the climate and driving conditions.

Check the condition of the Oxygen Sensor(O2), for it can make your engine run too lean. If your mixture is too lean then it will not combust and pump raw fuel out the tailpipe, but not enough to look like smoke. Your engine will appear to operate normally with an almost undetectable miss. If you don't want to get your hands dirty an emissions test will tell you by reporting an excessive amount of Hydrocarbons. Bad mileage can be contributed to O2s reading to lean or to rich, but if it were to rich it generally smokes out the tailpipe.