What can cause horrible gas mileage problems?

[Kdubslugga]

A friend of mine is getting really bad gas mileage in his 90 LX 5.0. What are some things to look for?

 

[Stanger007]

Plugs, cap, rotor, o2 sensors, air filter, plugged cats, fuel filter

 

[Kdubslugga]

thanks for the reply man

 

[charlesw6954]

and the driver.

if you floor it all the time then yea you will loose gas mileage. like just recently i got 18 mpg in town with out even getting on the gas. but i got some bad rear tires so that might go up a bit

 

[JaysGreenLX]

A sudden and drastic change in mileage is usually associated with O2 sensors. But it could be any of the things mentioned.

 

[smigle]

Ford V8's :d

 

[chevyeater]

high price of gas.lol

 

[MadMatt5oh]

OK. Im going to try to help make this thread productive. How do you check to see if your cats are plugged?

 

[JaysGreenLX]

Usually when cats are plugged a car will be very sluggish after it warms up. You can put your foot to the floor and only be going 10mph. The headers will start glowing and you won't feel as much exhaust exiting the tailpipes. Its a little harder to tell with a true dual exhaust car but it might be something to look into.

 

[HISSIN50]

dont forget the ECT. it senses coolant temp and gets the car into closed loop when sensing warm enough temps. if its reading incorrectly (telling puter car is cold when not), it will run in open loop.
i would check codes. helps diagnose o2's, etc.
good luck.

 

[Maryland Stang]

Ford V8's :d

Nah, I don't think so. My '92 gets 32+ mpg highway at 65 to 70 mph.

 

[HISSIN50]

hey now, i get 12 mpg with my size 14. LOL.
also if one really thinks cats are plugged, drill a small hole just in front of them. if air is flying out the hole, that suggests they are bad.

 

[Stanger007]

fuel injector's dirty/need to be cleaned?

 

[MadMatt5oh]

Usually when cats are plugged a car will be very sluggish after it warms up. You can put your foot to the floor and only be going 10mph. The headers will start glowing and you won't feel as much exhaust exiting the tailpipes. Its a little harder to tell with a true dual exhaust car but it might be something to look into.

So the engine would generally be sluggish as well? It sounds as if it would be difficult to reach higher rpms in idle with such a condition? Ive never had any of this happen to me - with any car. How is it avoided?

 

[Stanger007]

Buying an off-road exhaust will permanently fix clogged cats.