Is this normal gas mileage ?
Thread Starter
Teching In
Joined: Aug 2020
Posts: 48
Likes: 3
Is this normal gas mileage ? So I’ve read some of these forums of members getting about 150 miles until they have to fill up again but they’re tuned or have a bunch of mods.
My fuel sending unit is bad because my gas gauge doesn’t work so I go by the gas mileage. I read the tank for a 94 trans am v8 takes 15.5 gallons. I figured with city driving I would at least get 180 miles before filling up. But It only gives me 150 miles barely. The only mods are 18inch tires and wheels. Magnaflow catback and that’s it. I did a tune up too when I bought it. I got a petris ventilated opti with plugs and wires. But other than that it’s stock. I sometimes step on it but not really. It’s not my daily driver by the way.
Just wondering if this is normal ?
I will do LTH and Cam in the future but at this rate I’ll be lucky to get 120 miles before I fill up lol
My fuel sending unit is bad because my gas gauge doesn’t work so I go by the gas mileage. I read the tank for a 94 trans am v8 takes 15.5 gallons. I figured with city driving I would at least get 180 miles before filling up. But It only gives me 150 miles barely. The only mods are 18inch tires and wheels. Magnaflow catback and that’s it. I did a tune up too when I bought it. I got a petris ventilated opti with plugs and wires. But other than that it’s stock. I sometimes step on it but not really. It’s not my daily driver by the way.
Just wondering if this is normal ?
I will do LTH and Cam in the future but at this rate I’ll be lucky to get 120 miles before I fill up lol
Thread Starter
Teching In
Joined: Aug 2020
Posts: 48
Likes: 3
I actually have run it until it doesn’t turn on anymore. Both times have been under 150 miles a tank. Kind of odd. I bought the car last year and did a whole inspection (1 owner) and everything checked out. Just changed all the fluids and all of the mentioned above mods. I Still find it odd I get horrific mileage on a stock car.
Again I understand it’s a v8 so it’s not an issue, just worried maybe there’s something I need to check out that I don’t know.
Again I understand it’s a v8 so it’s not an issue, just worried maybe there’s something I need to check out that I don’t know.
TECH Resident
Joined: Oct 2006
Posts: 993
Likes: 173
From: Euless, TX
MPG is directly proportional to your right foot. Even still something seems off. I once got 9.7 mpg city in my 5.7L powered Express van making about 350 hp but it took alot of idling and foot to the floor acceleration out of every stop to drag it that low. Normal city mileage for that 6,500 lbs brick is about 11-12.
Auto? I have a M6 and when stock was getting high teens when goin' to town. Mid to high 20's on the freeway. Depended on how much foot I put on the gas pedal. My current engine is getting 12-14/17-20.
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Teching In
Joined: Aug 2021
Posts: 32
Likes: 3
A few things to consider, hills and inclimbs especially if you drive the same streets. Even the tiniest inclimbs will eat mpg.
Some gas stations use **** gas. I put in mine what makes the car feel the best. I dont Care about saving $2.45 on a tank. So keep that in mind.
Also you drive once or twice a week, evaporation eats a gallon a week.
Other than that, what brand o2s are you running, plugs and wires all good? Maf clean or dirty? And also check your tire psi. It changes from cold to warm weather. I check my tires at least twice a year. Deflate in cold weather, inflate in warm weather.
Some gas stations use **** gas. I put in mine what makes the car feel the best. I dont Care about saving $2.45 on a tank. So keep that in mind.
Also you drive once or twice a week, evaporation eats a gallon a week.
Other than that, what brand o2s are you running, plugs and wires all good? Maf clean or dirty? And also check your tire psi. It changes from cold to warm weather. I check my tires at least twice a year. Deflate in cold weather, inflate in warm weather.
Thread Starter
Teching In
Joined: Aug 2020
Posts: 48
Likes: 3
So I put Shell V-power, I got new plugs and wires. New opti. Tires and wheels all new. Maf all clean. New engine filter. Literally everything is new along with fluids. Got the car last year and since last year I’ve put 1k miles. When driven there’s no street inclines that I’ve taken. Catback new. Again I figured I would get at least 180 miles to empty but barely get 150. I mean I don’t care I was just wondering if maybe something could be wrong that I might be missing since many ppl here mention getting around 180 miles until they fill up again and they’re more modded.
Did you check if someone might have swapped your PCM, or put a wrong tune? Do you smell fuel? I would also check make sure your injectors are stock.
BTW, I put my 95 Z28 back to stock, and im getting 390 miles to a tank.
BTW, I put my 95 Z28 back to stock, and im getting 390 miles to a tank.
Thread Starter
Teching In
Joined: Aug 2020
Posts: 48
Likes: 3
Hey guys, from my understanding the car was stock when I bought it. I bought it from a 75yr old man. I’m not super versed mechanically but I know for a fact the car has never been tuned nor modified. I did google to see how big the gas tank is on the 94 Transam and it stated 15 gallons so that’s what I assumed. Idk weird. I’m currently at 145/150 miles until I’m empty.
You're putting in 15 gallons at 150 miles? If so....your fuel mileage is low.
First thing I would do is check the exhaust manifold bolts. LT1's are notorious for loose/missing bolts. The resulting exhaust leak will put a crush on your fuel mileage.
KW
First thing I would do is check the exhaust manifold bolts. LT1's are notorious for loose/missing bolts. The resulting exhaust leak will put a crush on your fuel mileage.
KW
Launching!
Joined: Aug 2020
Posts: 205
Likes: 70
From: Phoenix AZ
Couple problems here.
1. you live in Chicago or Chicago area
2. driving short trips never gives car a chance to warm up - Chicago
3.you have only put 1000 miles on car - bunch of short trips -stop and go traffic -Chicago
Take a leisurely drive out to burbs even the country
1. you live in Chicago or Chicago area
2. driving short trips never gives car a chance to warm up - Chicago
3.you have only put 1000 miles on car - bunch of short trips -stop and go traffic -Chicago
Take a leisurely drive out to burbs even the country