Bad MPG and Misfires...

[phoenix6]

My car has been getting worse gas mileage lately, for almost 3 weeks, I havent checked how much exactly but Im going through tanks faster all the sudden, somethings up. On top of this my acceleration is slightly hesistant, esp from first gear, its not quite as bad from 2nd - 5th, but somethings wrong. My plans to fix this today were:

Spark Plugs + Wires
Fuel Filter
Clean my K&N (its been like 5 months)
Add Injector cleaner

Is there anything else I need to check into? Dont know if this helps either but my car is at 77,800 miles, daily driven, has synthetic oil and was changed at 74,500 last. Tires need some air in them too, anyways, any help would be appreciated.

[FireFighter]

Its time for an oil change :D Could be an O2 sensor also, is the ses light on?

[phoenix6]

No the SES light isnt on, and oil change with synthetic I thought was around 4500 to 6000 Miles, not the regular 3000 - 3500.

[HeadyFirebird'00]

what kinda mpg are you calculating? i know what you mean about the gas milage i cant figure mine out either. i did every tune up possible except fot the EGR. i dont want to mess with that.

[Die Ford V8]

flush your coolant. thick or crappy coolant going through the engine has made a few cars on this sight get bad mileage.

also driving with less accesories on saves me mileage(headlights, heater, AC, etc.) only a little bit, but it still counts.

change your pcv valve too. make sure your cat isnt plugged and open up the throttle a few times a week to keep the carbon from building up(if you dont drive hard already)


with all this you should be good to go and it all should help.

just an FYI, you get better mileage with the windows up.

[AlienInv8r]

By hesitant acceleration, do you mean it's misfiring as you try to accelerate? It sounds like it's the all-to-common plugs/wires. Give it a go after you change those today, as plugs and wires on these cars are notorious for causing the misfires and hesitation. Your oil wouldn't cause those kind of problems that soon, especially if it's at the proper level. I'd go ahead and change the items you are planning on today and see where that takes you. You're on the right track and those items are definitely good first tries to fix the problem.

[phoenix6]

I didnt get to the fuel filter tonight bc the Sparks were a *****, I had such a hard time bc I screwed up the order, I thought it misfired b4, my god it was acting like it wanted to die LOL. I got all the stuff today but only got to the new bellow (which was easy and perfect!) and the spark plugs, which fixed my hesistation problem so well its scarry O_O. Fuel Filter will def feel better along with injector cleaner. Im gonna get to the PCV Valve also, see what that does. After tonight tho I can def feel it running better than normal, almost like new.