NeedaV8foundation

iTrader: (4)

i just bought my 98 trans am about a month ago, it has 63k on it and has a 6 speed. for some reason i only get about 150 miles to the tank. i replaced the MAF with a new one from SLP and cleaned the injectors. i also did an oil change along with all of the other fluids. what gives???? im going to changed the fuel filter probably next week, i also get a new exhuast set up as well, i ran the diagnostics on my car and it was throwing a 3rd cat code. i erased it but it keeps comming up... is it my cats?

discostu

hate to ask but how are you getting your miles. with the trip and with the gallons added your just your gauge?

NeedaV8foundation

iTrader: (4)

yea, i fill and reset trip

discostu

any other mods done to the car or is it stock

HoLLo

iTrader: (17)

If you are having a cat code, i would definitely fix that first. A bad cat leading to the rear O2 sensor will cause your car to think that its burning improperly and has to compensate. Also change the spark plugs.

wssix99

iTrader: (5)

Normal for Chicago - In city driving, my 60K WS6 got 12.5 mpg. So, if your fill-up was around 12 gallons, I'd say you are normal for city driving on an engine with carbon build up.

If you do a carbon cleaning, (I did a MotorVac CarbonClean - you'll find many posts here for SeaFoam, which does a similar job.) you should see at least another 3 mpg.

You'll be happier when you take a road trip on the highway - set the cruise control at 65 mph and you'll more than double your mileage vs. the daily stop-and-go.

The price of gas is brutal in Chicagoland. My carbon cleaning has paid for itself many times over.

brad8266

iTrader: (23)

WOW, I have a built cammed/head motor and I get more than that doing city driving only.

sixvi6-camaro

iTrader: (9)

First off stop just deleting codes without actually doing anything to fix the problem. what are the codes the pcm is throwing? if it is a cat related code it could be anything from a bad O2 to a clogged cat both of which will cause bad mileage... also Cold weather = poor gas mileage. The car spends a lot more time in Open loop as the O2s heat up which uses a ton more fuel. I have HPT logs of cold starts when the temps are in the single digits where it takes 10-15 minutes of driving before the engine temp comes up high enough to go into Closed loop. While its in open loop and warming up the car runs very rich and will use a ton of fuel. now if you are driving in this cold weather and only taking short trips the car will never completely warm up and will use a lot of fuel.

My car gets around 180 miles a tank in the winter.. summer time I get around 200. this is with an A4 and a big stall too all driving in city traffic back and forth 40 miles a day.

NeedaV8foundation

iTrader: (4)

i read the codes today bank 1- running lean, bank 2- running lean, bank 3- 3rd cat flow restriction, and same for bank 4.... The car is stock, other than MAF, i looked into seafoaming.... and i realllly dont like the idea of sticking that crap in my brake booster line, i mean has anyone had any bad experiences with seafoam? i might try it out before i change out my exhuast. anyones thoughts?

FMX05

iTrader: (3)

There are 38 pages with reviews on seafoam in the sticky on the top of this section. I just used it on my Firebird yesterday, and my DD s10 blazer the day before. Both of them idle smoother. It even took away some of the valvetrain noise on my bird'. If you follow the instructions in the sticky you really cant go wrong. My car didn't try to die while the hose was unhooked so it was easier. Use a funnel, pour it slow. It works. Combine that with seafoam in the tank and a fuel filter change after that. You should see a few EmmPeeGee's.

waterbug1999

iTrader: (3)

If I were you, I would change the 02's and plugs at the same time.. Its sensing a lean condition (due to bad 02's) and dumping in more fuel then needed probably.

AR15 guy

iTrader: (1)

My lt1 car went from getting 250 miles to a tank to 150. It was my fuel filter.

tspence45

iTrader: (30)

I think I need to do a fuel filter change sometime soon. I'm only getting around 170-180 a tank with mine. Course, I have a bad o2 sensor and the plugs and wires probably need changed. Could a bad exhaust leak cause mpg to go down and for it to throw the o2 sensor code? I've got a horrible exhaust leak at the passenger header/y-pipe connection.

wssix99

iTrader: (5)

Depends on the city you are doing your city driving in. There are as many as 20 intersections per mile where we live. I get much better mileage in smaller cities and 30 mpg on the highway.

In the upper Midwest, we also have a special winter blend of gasoline that also drops the mileage a little bit.

Slo-Mo-Shun

iTrader: (2)

Enlighten me on this.... I can't see a plugged fuel filter causing the engine to use more fuel.?....

unless this is a fuel filter with an integrated fuel pressure regulator and the regulator itself is faulty.

I would think a bad tank of fuel... before the fuel filter.