[Black03Mach]

I feel like my gas mileage has dropped significantly since i bought the car. I seafoamed it at the end of summer and i feel like im putting in 10 dollars a day. I need a oil change, but what else should i get looked at and changed while im doing this to improve mileage. Ive also got full exhaust intake and no tune.

[97mustanggt]

clean your maf, clean your air filter and oil it up thats if its a knn, etc.
change your fuel filter, also if you have never changed your spark plugs, do it.

[Everett]

No tune may be your issue too... Start with cleaning er up and go from there

[drazga97]

what they said + check your tire pressure.

[rst1523]

all good ideas.....i would first try taking your right foot off the floor!! lol do not get the e3 plugs by the way my car ran light sh!t with them. and i went back to autolight +2s i believe and it fixed everything. with the e3's it felt as if the motor was backfiring and you could see it shake really badly via shaker. This was under a light load too. I would say do all those things listed also change your trans and diff while you are at it cause you bought it used and you don't know when it was done last and that can affect your gas mileage too. Also go to your local oil change place and ask them how they do a complete fuel injection service. Just have them show you. They will have this bottle with a tube coming out of it and it is attached to a flow control valve. make one and put half a bottle of seafoam in your tank and the other half in the bottle you made or bought. Connect the line to a vacuum line leading to the top of the intake manifold and what you need to do is run the seafoam as slow as possible through the intake manifold, so a clear inlet tube would be good to by so you can see your flow. run the bottle dry. when done raise the rpms to 2k and hold it for about 30 secs. if the car dies when you fist give it gas that's ok just restarted and be ready to give it gas to get it started. now that it's cold outside your are going to see alot more white smoke than you would in the summer. this is ok too. and it's going to smell too. after hold the gas at 2k for a bit, quick rev it to about 5k a couple of times to get the rest of the chemical out. it may smoke and smell for up to a week after that be it's ok. What you have done is clean all the carbon deposits in the upper intake, runners, back of your vavles, and helped clean more of you combustion chamber too. Do that about every 15k. NO E3'S

[bigjohnstud4200]

how many miles? Maybe o2 sensors?

[majorownage]

1. keep your foot out of the gas
2. Keep your air pressure to at least what the recommended pressure is.
3. Alignment
4. low viscosity oil
5. OEM plugs or hotter
6. Air filter

Seafoam is spectacular... but really doesn't do that much. Think about this: carbon buildup would increase your compression ratio, therefore increasing your efficiency. Most of that smoke comes from your cats anyway...not your engine.

[Calogero6685]

So for my Black 03 Mach 1 (Nice car BTW!) Should I use autolight +2 as well? Money isn't a factor.

[rst1523]

Originally Posted by Calogero6685 So for my Black 03 Mach 1 (Nice car BTW!) Should I use autolight +2 as well? Money isn't a factor.

i have not had any problems so far, so yes i would say run them

[Calogero6685]

Also, Majorownage. You DON'T want carbon deposits in your engine. No matter what. It creates hot spot and once you see a hole in a piston from excessive heat then you'll change your mind about keeping your engine clean.

[majorownage]

Originally Posted by Calogero6685 Also, Majorownage. You DON'T want carbon deposits in your engine. No matter what. It creates hot spot and once you see a hole in a piston from excessive heat then you'll change your mind about keeping your engine clean.

We were talking about efficiency here. Of course carbon build up is unwanted.

[Black03Mach]

I bought the car with 33000 miles, it now just rolled over 50. I just had the O2 sensors changed. Bought some new plugs, fuel filter and MAF cleaner and im going to wash out my filter when im doin all of the above.

Hopefully it works, I havnt been driving aggressively but my fuel gauge fluctuates with how the car sits and it drives me fucking crazy.

[rst1523]

Originally Posted by Black03Mach I bought the car with 33000 miles, it now just rolled over 50. I just had the O2 sensors changed. Bought some new plugs, fuel filter and MAF cleaner and im going to wash out my filter when im doin all of the above. Hopefully it works, I havnt been driving aggressively but my fuel gauge fluctuates with how the car sits and it drives me fucking crazy.

this must be your first mustang. The fuel sending unit in these cars have retarded issues. it shows you have less gas when parked facing uphill and more when facing downhill. It's just one of those things.

[Black03Mach]

Originally Posted by rst1523 this must be your first mustang. The fuel sending unit in these cars have retarded issues. it shows you have less gas when parked facing uphill and more when facing downhill. It's just one of those things.

you guessed it, i came from a grand marquis.