Loss of MPG After Seafoaming

[yaitisme]

I have a 1992 Tercel with 135k miles and a 5-speed trans with a 3E-E engine. The first three tanks of gas gave me a consitant 40-43 MPG. After installing a cone filter and doing the Seafoam thing to the intake and gas tank I have been getting consistanly 31-34 MPG. I have since pulled the cone and installed the original intake and have reset the the EPU several times. A friend of mine had similar results after Seafoaming his 93 Civic. Seems pretty drastic loss of MPG, with no engine light, after doing something that should be good for the engine.

[ToyotaTechGeek]

well, probably due to a few things, but here's a start:
1) you like the way the intake sounds now and you think it sounds more performance-like, so you flog the car much more than you did before hence losing mileage.
2) you are getting 'more' air into the combustion mixture and your 02 sensor [1. got kinda gooey from the seafoam or 2. is just old anyways and needs to be replaced] so if the 02 sensor is bad and/or if there's more air and the 02 sensor 'senses' it, it'll richen the mixture therefore the fuel is agagin affected. see #1.

[yaitisme]

Thanks for the info. The sound of the cone was pretty cool and I was driving harder do to the sporty sound but at todays gas prices that did not last long. The stock air box is back in and my wife is using it as her daily driver and she does not drive hard.

As far as the O2 senser... I seafoamed the first time with the orginal O2 senser in it, then replaced with a new Boush senser. I did seafoam the engine a second time with the new O2 senser (because I didn't get the extreem exhaust smoking as other did) and added much more than the first application (1/3 to 1/2 a can).

Is it possable to damage an O2 with seafoam or just gum it up?

I will try pulling the O2 tonight, any method for cleaning one?

thanks

scott

[ToyotaTechGeek]

can't clean one. they go bad generally about 60k miles.

[Tercel GTS]

Keep in mind the car runs richer during winter.
How long do you warm up the car before driving?