Not to be a wise-***, but low gas milage can be caused by running too rich or also by having poor compression especially on an older, worn motor.

You might want to have a compression check especially if you can do it yourself. This would also explain power loss.

It it were me, I would do this. Also, this forces you to pull the plugs and look for indicators coated with oil or being rich.

Bad O2 sensor can cause a rich condition.

Look at it this way, if the a/f is supposed to run at 13.5 to 1, but your car is at 11.5 to 1, that would be a 15% reduction in fuel economy.

BTW, I get 22 mpg on a 380 rwhp car. That is because I have a good tune.

 

Ok, soo on checking the o2 sensors what should i do?? also as soon as i get a troque wrench i will pull the spark plugs and see if anything is wrong with them. the only way to check the a/f ratio it a dyno right?? also when i get the money to upgrade to a k&n will i see better fuel economy?

my car is getting better in gas, but feels worst in power, i got almost 100 miles on half a tank, then started to let my foot go alittle further to the floor and wasted the second half in about 75 miles. also is there any way to retune my car without having to get something like a SCT or diablo, or running a dyno. because i'm low on money. and saving gas will help save money

 

I don't think you need a torque wrench to remove the plugs. It would be nice to have, but not a need to ensure the plugs are ok. I bought a ten inch extension from autozone with the spark plug socket attached and this allows me to do plugs in no time and without worry of the attachments or socket staying down into the head. Just check the plugs with the heads cold or barely warm. Don't try to pull the plugs right after you have driven for a long stint. Check with the others on here about whether to anti-seize the threads or not. I know that is up for debate with the aluminum heads on these cars.

 

also they make a socket with a cut in the side of it to remove O2 sensors. It is a must if you do it yourself. If you have never done them since owning the car and aren't sure if they have ever been done and the car is fairly high in mileage, then do them as a regular maintainence item. Don't make the mistake I have and use anything other than the Ford style O2 sensor. Get with Randy on them, he has a good price on them.

 

For removal, a torque wrench is not needed but putting it back in, it's a mistake to not use one since our heads are Aluminum and have barely and threads in it for the plugs so over tightening will cause problems. Also, just use anti-sieze since it's there to prevent galling on the threads.

 

ok soo today i pulled one of my spark plugs and it has a white layer around the tip. i didn't have very much time soo i put that back in properly and wanted to know what that white layer was

 

The white you saw was probabaly the insulator.

 

Was it REALLY white, or just look like a dusting? White means a lean condition. The white insulator should look tan.

 

it was a dusty white. and when i get some money what type of plugs do you reconmend

 

Stick w/ the stock Motorcraft plugs. However, if you have to drive a good distance to get them, Champion, NGK, and Autolite are all good replacements.

 

Ask Randy for his take. He is a seasoned racer. You could go one step down colder. I prefer copper plugs and not the platinum. Autlite 103's or going with the stock heat range in a copper plug would be a nice way to save a few bucks and get maximum spark to your motor. It sounds like you were running a tad lean and a spark plug change even to the stock motorcraft plugs can greatly improve a cars performance if they haven't been done before. I believe the motorcraft stockers are AWSF-32C. You could go to the 22C's which are one stage colder. I would seriously consider a tune even on a stock motor to help correct the fuel issues and let you know what you are reading at.