Car getting horrible MPG

**blueguy** · 06-17-2009

Originally Posted by Mercenary

I'm gonna head out in a lil bit to see if the check engine light comes on again. Would two cans of seafoam be too much? I was thinking of using one just for the gas tank and the other for the crankcase/vacuum line.

Um, yeah...it says on the bottle how much...I think like a 1/3 or 1/2 a bottle does the trick.

**BANDIT** · 06-17-2009

Like blue says, do what's on the label. I waited til my tank was almost empty then put in a full can and filled up. That way I made sure I was getting a good mix.
I've heard on different forums that you can't use too much Seafoam as it can't hurt the motor, that's why I did mine a day apart.
Just follow the directions and you'll be fine.
Good luck!

**Mercenary** · 06-19-2009

I drove the car around a lil bit yesterday and I'm getting around 17. I didn't throw a code tho so I guess it's time seafoam it and wait for a code to come up.

**tjvdubsport** · 06-19-2009

mines getting 14.7 mpg and no check engine lights . put a fwi, and some 605 autolite plugs this was after i was getting that awefull mileage ...i already cleaned the MAF sensor and the TB ..
what could be wrong ? havent changed the fuel filter nor pcv valve .. i think im gonna return to the 606 oem plugs ..

**blueguy** · 06-19-2009

Dropping not even 1 heat range is not going to give you that bad of mileage...something else is wrong.

**Mercenary** · 06-19-2009

Originally Posted by tjvdubsport

mines getting 14.7 mpg and no check engine lights . put a fwi, and some 605 autolite plugs this was after i was getting that awefull mileage ...i already cleaned the MAF sensor and the TB ..
what could be wrong ? havent changed the fuel filter nor pcv valve .. i think im gonna return to the 606 oem plugs ..

All I can say say is start with a basic tune up and go from there (cheapest first).

**Mercenary** · 06-21-2009

well my coolant code went away but I'm still misfiring and getting bad gas mileage. Good news is that I got a 306 code (number 6 cylinder misfire) so that leads me to believe it's the coil packs and I'll get some tomorrow.

**Liquifire** · 07-08-2009

any update........was it the coil?

**Liquifire** · 07-28-2009

just curious.......any new info on this issue?

**Mercenary** · 07-29-2009

Sorry for not updating sooner. I'm dealin with alot of crap right now and the GTP is just one of them. I replaced the coil packs and the wheel bearings yesterday I got 25 mpg on the highway. So far it's back to the way it used to be but alot of my mechanic friends are tellin me to get rid of it because they think it's gonna nickle and dime me to death. So I'm saving up and trying to find another car.

**Mercenary** · 08-04-2009

Just adding a small update. The car is down to about 20 MPG and still misfiring when I reach about 40 MPH. Right now I'm just praying the car will hold out a couple more months because I don't have anymore cash to sink into it.

**Mercenary** · 03-05-2010

YouTube - I think my GP is dying

Not really an update just looking for ideas on what this noise might be. I think it's a dead lifter but I'm no expert.

**Bio248** · 03-06-2010

i cant tell you the video helped me, but if its ticking a lifter could be it. usually the lifters are pretty beefy, but it happens.

how did the plugs look when you pulled them? youve checked for exhaust leaks? the injectors do tick quite a bit.

**Mercenary** · 03-07-2010

I'm due for a oil change in a lil bit and I'm gonna replace the plugs then but when I first pulled them, this was a couple months ago, they seemed fine. How should I go about checking exhaust leaks? (yea I'm a newb)

**Spartan GL** · 03-07-2010

might be the o2 Sensor.

thats what my problem is

**2000GTGP** · 03-07-2010

front or rear o2? im in the same boat. im getting ~15mpg although a driver mod might fix mine XD (high rpms are good)

it also sounds like a have an exhaust leak sounded like so for couple of months but ive had my oil changed twice since ive heard that noise, they do a multi point check when changing oil around here, and the sheet they give back report the exhaust in excellent condition.

**Mercenary** · 03-07-2010

Originally Posted by Spartangl

might be the o2 Sensor.

thats what my problem is

Yea someone brought that up before. At this point it could be alot of stuff, so I'm gonna get it scanned. I've just been trying to avoid doing that.

**Spartan GL** · 03-07-2010

i wanna say front o2 sensor.

but get both front and rear checked.

-Spartan GL

**16MustangVet** · 03-08-2010

Check your vin # can call a dealer to see if the catalaytic converter is under warranty 100k warranty and my 02 GP did all the same crap replace plugs, wires coils egr maf sensor filters nothing worked until i cut the cat off and it ran great open exhaust it was a plugged cat making my car go into limp mode and ****ty mpg and no power could barley drive around town.