Bad gas mileage..

[2000pontiac6]

I have a 2000 3.8L firebird with a catback and intake... My car has been getting no better then 17mpg for the longest time. 17 at best. I don't do much long distance driving but come on, my V8 friends are getting the same or better gas mileage. Should I take it somewhere to be checked out? Could my cat be clogged? What can I do to change this?

[bandit95]

is it an auto or m5? do you mainly do city or highway? my 96 v6 with an a4 usually got about 17 or 18 mpg between city and highway. but dont feel bad, the trans am i got now gets about 12mpg.

[2000pontiac6]

Its an auto... I mainly just drive it to school and friends houses. I just don't understand how my friend with V8s get the same or better, even if they are mostly older years.. I can't believe the mpg the ls1 guys are saying they get.:dunno:

[quicky06]

welcome to the club of bad gas milage. i move up to 16mpg from 8 with my 88 blazer

[bandit95]

alot of it can also deal with the gears you got, if the car has the time to really warm up in the time it's driven, and you could check to see if anything needs a tune up, the tire pressure is good, and so on. the ls1's do accomplish some amazing gas mileage especially on 6 spds. even compared with the v6's. the gears on your car should either be a 3.08 or a 3.42 gear, depends on if you got the sports and performance package or not. unless it's running badly or smelling like a rotten egg your cat is ok. best of luck to ya.

['94 Camaro RS]

if you think about it the v6 has to work harder to get the car moving unlike the v8. but you should still get more than 17 mpg. did you check the plugs,wires, tire pressure??

[PaganEgyptian]

Even with my Hopped up V-6 I got 32mpg running a constant 65-70mph for 450 miles on the highway, and around 16ish city. But then again, I do not have a cataluytic converter or EGR.
When have your plugs been changed last?????? I would do a tune up with new plugs, wires and filters (air and gas) something is not working efficently.... not much else computer-wise like EGR or such would cause that.
Go to your local Muffler shop and have them do a backpressure check on your catalytic converter. too much restriction will also kill yoru fuel mileage.Good Luck
-Tim

[NE98LS1]

wow, that sucks, i get around 24 with my 3.23s and a V8!

[supermando]

I used to get better than 20mpg with my 1994 firebird V6 with 3:42 gears and cold air intake. I have a 2002 WS6 now and it's true that with the extra HP the trans am's don't have to try very hard to get around. With my firebird I would constantly pass 3000 rpm with normal driving. Now with my WS6 I can get around with some pretty descent acceration and cruise the highway at upto 65mph without ever breaking 2000 rpm. I get the same mileage now as I did with my V6 firebird. About 22-25 mpg.

[m6speed]

check plugs and wires, cats, air filter, and your o2's

[TXMaro]

sucks.. I'm gettin 23 combined with 3.42s and exhaust - headers. Intake goes on this weekend. Like they said.. tune up.

[Raoul-Duke]

http://www.decordova.org/decordova/images/imagess_p/levy_bigbaby_lg.jpg

[Jeep41]

This one was to easy...

[iLIKEtransAMS]

damn man, I just figured out I get about 14 mpg in town. I drive a 95 3.4 firebird

[myk02k]

my Z went from 180 miles per fuel-up to 260 miles after a sea foam, fuel filter swap, 3000 mile drive, and new tranny. Though I don't recommend you driving 3000 miles and getting a new trans for gas mileage, I would check to make sure everything is well-fitted on the intake and its not leaking anywhere, swap out the fuel filter and sea foam it to try to clean up the fuel injectors. If that doesn't help then get it checked up on. You may have just bad injectors or spark plugs. If you had a clogged cat, I think that changes the exhaust tone.

[myk02k]

(I put the wrong post here, sorry)

[98bpmta]

two words............ fuel filter :yup: :yup:

[2000pontiac6]

my Z went from 180 miles per fuel-up to 260 miles after a sea foam, fuel filter swap, 3000 mile drive, and new tranny. Though I don't recommend you driving 3000 miles and getting a new trans for gas mileage, I would check to make sure everything is well-fitted on the intake and its not leaking anywhere, swap out the fuel filter and sea foam it to try to clean up the fuel injectors. If that doesn't help then get it checked up on. You may have just bad injectors or spark plugs. If you had a clogged cat, I think that changes the exhaust tone.


Stupid question, whats the sea foam?:hide:

[myk02k]

You can purchase Sea Foam from autosports store. There's different direction as to where you can put it in your car (my bro put it in a brake booster vacuum, i think you can put it directly into the throttle body. It's suppose to be a type of treatment to clean out your fuel injectors, cylinders, block, and catalytic converter.

[quicky06]

i went from 15 to 20 by switching to full synthetic(still on the first change) and plugs (platinum +4) i replaced my fuel filter about 5k ago at the most same with pcv. i need to get the radiator flushed and new shocks and struts, but what else can i do for gas milage besides not driving like an ass?

[2000pontiac6]

You can purchase Sea Foam from autosports store. There's different direction as to where you can put it in your car (my bro put it in a brake booster vacuum, i think you can put it directly into the throttle body. It's suppose to be a type of treatment to clean out your fuel injectors, cylinders, block, and catalytic converter.

Thanks maybe i'll try this.. however i did use an injector cleaner recently (which did get my up to 19mpg) but maybe next time i can do that

[myk02k]

fuueeeeeeeeel filteeeeeeeeeeer! just to proove that it HAS to be it. If your going to use Sea Foam, you might as well get premium once and get a bottle of octane booster. In theory, higher octane burns cleaner in addition to cleaning out hydrocarbons. Check your tires, get rid of any junk in your trunk, and w/e else you see fit.

[Wesman]

V6 + Auto = Bad fuel economy.

Its just the way it is, the V6 engine isn't very efficient to begin with, and when paired to a tall ratio automatic in a 3400lb F-body, its just not going to get good gas mileage.

Sorry :dunno:

[myk02k]

umm...here = V8 auto and although it is not great, I went from 180 miles to 260 miles per tank after the sea foam & fuel filter swap.

[Wesman]

umm...here = V8 auto and although it is not great, I went from 180 miles to 260 miles per tank after the sea foam & fuel filter swap.

Thats a big jump!! You're engine and fuel filter must have been really dirty.

Its funny how the LS1 autos get the same of not better fuel economy than the V6 autos, I think it has to do with the LS1 just being a more efficient engine, along with the fact that it hardly has to turn any RPM's in normal driving since it has so much low end power & torque :burnout:

[myk02k]

IDK about that one...my older brother has a V6 A4 Firebird and he claims to get way over my gas mileage (although it may be an ego thing). The one thing that did affect his mileage after a while though was because his rear axle was broken. When you would cruise in his car with no gas or brake, the car decellerated as if he threw sandbags out the window tied to his car.

Anyways, I see it also like with the V6, especially in redlight-to-redlight moving that it won't be wasting as much gas since it doesn't give as much push. I'm always the first in line on these red-to-red traffic light stops, and it's not that I'm trying my car gives a decent push of gas and power after it hits 2nd.

[myk02k]

the fact that it hardly has to turn any RPM's in normal driving since it has so much low end power & torque :burnout:

Can't argue that, although it may be less efficient. At idle in drive on the brake I'm at 500 RPM. Last Night I wanted to see what I'd cruise at 2500 RPM, and I had to stop cuz traffic was building up. I got up to 85 MPH and my speedo was still climbing.

The best bragging I can do to a 4-cylinder driver is, "my camaro cruises on the highway at the same RPMs your car idles at.":notworthy:

[2001shpcamaro]

All i got to say is that sucks my 2001 ls1 with 90,000 miles gets 23mpg with 3.23 gears, driving the crap out of it!:) :beer:

[2000pontiac6]

Hmm I did get 23mpg last weekend... it was all highway driving to the beach and back

[myk02k]

Hmm I did get 23mpg last weekend... it was all highway driving to the beach and back

Yup. When I was getting 14.5 MPG I got near 18-20 MPG on my way to senior prom weekend 250 miles away.

[shady1504]

I have a 2000 A4 Trans Am and a 2000 A4 Firebird and I get way better gas mileage in my v6 than my v8. The v6 gets about 23mpg and the v8 about 18mpg. They both have 3.42's, headers, and intake. So I don't agree with those that think the v6 gets worse mileage than the v8.

[myk02k]

that's not what we're doing. i know the v6's should get better mileage, but when there's something wrong you lose mileage.

[josh0013]

well my 98 3.8L gets about 32 on the highway and 24 in town. And for those who said it take more to move the heavy car, well really it seems great. I think the buick motor is all you need in this car... the v8's are just for that extra power. many people think the v6 is for the poor people who can't afford the v8, but really i have a v8 and a v6 and i like them both the same. good luck with you mpg problem.

[V-8]

I wish the camaro worked like the newer v8's were,it uses 4-6cy for efficiency when power is not demanding and then all 8 when u need power

[MegaMan]

how many miles on the car? when was the last time you gave your car a tuneup? tires, plugs, wires, fuel filter, o2 sensors can all have an effect on your mileage. seafoam never hurts.

[Jason Leighter]

I agree with the last post. I have a 6 and driving style makes all the difference!