whats peoples average mpg on 3.4 setup?

hmm. if 17.5 is the tank size in my 99 then i think my gauge might be off which is leading me to put gas in sooner then i would and might be making it seem im getting worse mpg then i really am?

fill it up all the way... reset trip odometer and fuel used in DIC and go from there.

My 3.4 setup gets me about 32 highway 23 or so city? combined I've been getting about 26, usually in the summer it goes back up to 28 once they get rid of the winter blend junk.

But yeah unless you are warming up your car for 10 minutes everyday and crawling through traffic you shoulden't see less than 20.

yea ill fill it up and figure it out, ill post the findings in a few days lol.

Sorry to jump in but iv got a few questions...Iv got a 98 GTP and i usualy fill my car up when the DIC says low on it which is when it drops to the orange bit. When i do fill up at that point the DIC usualy says around 12gallons. Iv also herd our tanks are 14.5. So i worked it out that on 12 gallons (according to the DIC) i go about 190 miles. So how much do the tanks really hold? and why is my gas milage terrible...

they said earlier on page 1 or 2 that our tanks are 17.5 in anything 98+ i just got back from gas station and i put it 13.36 gallons on top of a 1/4 tank so its more then 14.5. anyway like i said i just filled my tank and i know something has to be not sealed correctly. cuz i can smell the fresh gas and when i take a turn it becomes a stronger smell. ill have to drop the tank again to find out. might be where im getting a p0440 from.

mine can hold 18 gallons

interesting...so yall think i should just push past the LOW that the DIC shows and hope its wrong? lol

well my first gtp with 3.4 pulley got 34 mpg, not an instant average. i filled it up and cleared the dic and got on the highway and went out of town and it stayed at 34.3 after i drove for a while. and city i got 19 if i drove like i had sense but that didnt last long lol. and my 1999 owners manual says 17.0 gallon tank

page 2 towards teh bottom it says 97-99 tanks are 18-19 gallons "he thinks. 00-03 had 17.5"he thinks" so ur 13 id say is wrong.

I got it i should just get a 1gal tank fill it up then drive till my car runs out throw the 1gal in and fill up. Yall think that will kill my fuel pump? cuz iv herd rumors about that

it will

they use the fuel to cool them.

ok then how do i go about finding out if im just getting piss poor MPG or if my gas gauge is off?

fill up and zero trip out. then see how many miles you got off that tank of gas.

well iv always done that but i need to know if my gas gauge is off. Because i go about 190 miles and the pin gets to the orange bit then my DIC says low and the low fuel light comes on as well as it only says iv used 12gal. So is my guage off or what?

im guessing but if thats correct your getting 12-13 mpg??? something is wrong with your foot or car. and gas hands in most gm's are funny, and wow your in lawrenceville i bought my first gtp from there off sugarloaf

Thats awesome man! But idk i dont have that heavy of a foot i do like letting it go every now and then but not enough to destroy the MPG that much...so how do i go about finding out whats up? any suggestion from anyone would be helpfull

well i say get you some seafoam and plugs and wires and check tires. and change pcv and coolant. and watch mpg go up. im trying to get my gtp back running because my sts overdoses off 93 lol

Well I just replaced the plugs we did run a full bottle of seafoam through the brake booster and I just got new tire and the PCB is new lol. So anything else I could be missing? >.<

I just bought a 2000 daytona 500 a couple weeks ago.I aparently need to do the same thing...its got 135k miles and who knows whats been replaced. I just refilled my tank did the math on my trip odometer and it says im getting 13mpg...somethings wrong. Dunno where to start but i guess ill get seafoam tomarrow and plugs and go from there....when it warms up im going to flush my coolent and replace the thermostat.

For seafoam where have people had the best results as far as putting it in? I know it can pretty much go in any part of the motor but wheres the best for just a quick clean?