Hey guys,

First topic on the forums and I just wanted to get some quick answers from a few people. what is your average mpg? I get around 15.2 which seems a tad low. I have no performance mods done to my car, although it has been kept up perfectly. Change oil every 2,000, plugs and wires have been changed, and other preventative matinence. Just wondering if anyone is in the same boat as me or if anyone has any ideas on what might be happening. Thanks for the help.

_________________

how do you drive?

i get 18-20mpg becuase of intown driving and the 2.93 gear ratio lugs the engine

_________________

92 LeBaron Convert: Turbo 3L 97 Grand Prix GT 4dr "Frankenstein": L67 4t65 swap
97 Grand Marquis: Summer DD 99 Grand Prix GTP: Top Swap Beater

I drive conservatively all the time. Do no accelerate into red light or stop signs, don't accelerate at an extreme rate. I baby it for god sake. There absolutely had to be something wrong with it. Also the exhaust has the rotten egg smell but I cannot figure out why.

_________________

Bad cat which is why your getting low gas mileage

_________________
02 Chevy Zr2-sl2,2"BL,Mtclassic II's,Flowmasters,duratrak lockers 3.73's gears
97 Dodge avenger-to many to list-Sold
02 Gp Gt- Intake,Gmpp,PCM,3In Dp.

See that is why i thought it was making the rotten egg smell to but a tech at the local exhaust shop said it is most likely not the cat but i dont know of anything else that would make it do that.

You do think that is the reason why such low mpg though?

_________________

Even with my mods I see about 19 in town, cant believe you would be seeing 15...DIC reading correctly?

_________________

i have checked with pictures of the pump when i got gas, dividing the number of gallons to driven miles on the trip gauge and DIC is spot on. i guess 02GTPguy is right. I am sick of getting this bad of gas mileage though seriously.

_________________

rotten egg=bad cat converter or failing cat converter

_________________

92 LeBaron Convert: Turbo 3L 97 Grand Prix GT 4dr "Frankenstein": L67 4t65 swap
97 Grand Marquis: Summer DD 99 Grand Prix GTP: Top Swap Beater

thanks Mater, Just called the exhaust place again and asked them how much it was to put a new cat on the car, they said it would be $275. Not as bad as it could be I suppose. I just want to get this problem fixed..

_________________

Why spend that much when you can get a aftermarket one for 150-175 i do believe and bolt it on your self. Four bolts and some time and you will have saved your self some cash and gained a little performance.

_________________
02 Chevy Zr2-sl2,2"BL,Mtclassic II's,Flowmasters,duratrak lockers 3.73's gears
97 Dodge avenger-to many to list-Sold
02 Gp Gt- Intake,Gmpp,PCM,3In Dp.

x2 with Tom on the failed/failing cat. Also, if it's never been changed before, now would be a good time to get a new o2 sensor. That should get you a couple extra MPG's once the car is also fixed though of course.

_________________

Dubs:00 VW GTI VR6, Low and Slow 91 VW GTI 8v, Shave the Bay!! 91 VW Cabriolet 8v, bitch Basket
GP's:04 GP GT, Past now G-Ma's Girlfriend's 97 GP GT, "Project Pink Power"

you can not get a bolt in one for that price. it would be a universal one that would need to be clamped on or welded in.

and then he would still have to cut the old one out with a sawz-all or other reciprocating saw


and only 4 bolts sounds good on paper but my midwest rust belt car was not that easy i actualy had t cut my old down pupe out becuase the bolteds rusted a way. i then had to weld a flang to the catback of the car. not a big deal for me becuase i all ready had to replace the resinator dot o rust

_________________

92 LeBaron Convert: Turbo 3L 97 Grand Prix GT 4dr "Frankenstein": L67 4t65 swap
97 Grand Marquis: Summer DD 99 Grand Prix GTP: Top Swap Beater

Thanks for the advice but there are ridiculous consequences in Missouri(and probably many other states) for doing your own cat work. If you get caught with a catalytic converter in your car you go to jail. You must have a license to change/remove a cat because the licensed people have a way of disposing of them properly.

_________________

memo to self do not drive though missouri as i currently have 8 cat converters in the my trunk

(4 from the merc (went to a 2 cat system from the newer cats flow better), 3 from the old F150 that is being turned to a 51 F1 and does not need cats now, and the one from the GP

in michigan you just bring them to the scrap yard and they give you money. it's i think $50 a cat right now lol

_________________

92 LeBaron Convert: Turbo 3L 97 Grand Prix GT 4dr "Frankenstein": L67 4t65 swap
97 Grand Marquis: Summer DD 99 Grand Prix GTP: Top Swap Beater

Yea same here but they are worth more so people were going around cutting the cat off of car so they had to make it illegal.

_________________

http://www.zzperformance.com/grand_prix ... &catid=110 Costs under 200. Just depends which one you get and thats with cat.

And i know how some midwest cars are i work on them all day long.

_________________
02 Chevy Zr2-sl2,2"BL,Mtclassic II's,Flowmasters,duratrak lockers 3.73's gears
97 Dodge avenger-to many to list-Sold
02 Gp Gt- Intake,Gmpp,PCM,3In Dp.

factor in shipping and it is over $200

_________________

92 LeBaron Convert: Turbo 3L 97 Grand Prix GT 4dr "Frankenstein": L67 4t65 swap
97 Grand Marquis: Summer DD 99 Grand Prix GTP: Top Swap Beater

I think mine was about that shipped. I could be wrong. But still, even then it's still illegal for him to do it.

_________________

2012 Ford Focus SE Sport
2012 MINI Cooper Clubman

I have ADHD and drive a Focus. Ironically.
Although gold dust is precious, when it gets in your eyes, it obstructs your vision.

Here's a Magnaflow 23405 bolt-in cat for $149.34 with free shipping: Brand New Magnaflow 23405 Direct Fit Converter
Same one I have on my car, and it's already passed emissions twice..

You have to supply gaskets, bolts, and labor. Maybe you could have it shipped to the shop that's doing the install..


There is another option, if your car has less than 120,000 miles: Advisory for All '01-'02 Grand Prix with SII 3800 Engine Concerning CAT Converter

thanks for all the imput guys, i should have the new cat installed within a few weeks.

_________________