Look man I'm gettin tired this sh!t I got a 95 Impala SS 5.7 350 V8 LT1 should be gettin 17 mpg in city but I'm only gettin 12 mp what the hell wrong with my car?
clean ALLL the filters, air filters, etc, idk if this is a legitimate difference but increasing air flow always helps out. My buddy with the same car as me put new headers, new exhaust, a new intake, and a new intake manifold, and he gets drastically better gas mileage than i do, my jeep cherokee 4.0L inline 6 gets like a whole 15 mpg TOPPS, gotta love the jeeps though
double check all the tire pressure, fill them to exact specs or like i did, fill them to 50 pounds if they rated at soemthin like 44 pounds, no joke, i actually feel a difference driving.
I got 22's I put 50 psi rear tires and 43 psi front tires just re-oiled my k&n filter changed plus and wires to hi-performace accel plugs and wires haven't put on msd distributor cap & rotor yet never changed my transmission filter, 02 sensors nor fuel filter
That's not that bad for an old car. Here's the real truth about MPG ratings by the manufacturers. The numbers you see on the windows, are all overrated/inflated. I wouldn't say it's a total lie, but to get those ratings, you'd have to drive in a "test" environment where everything is flat, no stop signs and smog. My Acura is suppose to give me 35-39MPG on highway and 31 in the city. In reality, I get around 20MPG. When the car was brand new, I'd say maybe 23MPG.
I'm happy I'm getting 12 instead 7 or 5 but it wasn't too long I was gettin 20 what is causing a 8 mpg loss? does high prformance parts like accell, msd, hypertech etc. use more gas than reg. autozone parts?
S.L.A.B., that LT1 350 probably just needs a tune up. I can tell you right now to be prepared to spend big money to get one. I've never had to tune up one of those yet and hope I never have to. I've talked to other mechanics that have and said they will never do another one. PIA!!
How long has it been since you got a tune up? Is your check engine (or service engine soon) light on?
I hope you used AC Delco plugs and good quality wires. How long ago was the cap and rotor changed? That's the fun part of the tune up. Heh Heh Heh The tune up aint complete without it. Make sure the air filter is clean, and spray the MAF out with brake cleaner. Also, are you running a K&N filter? If so, throw that under the back wheel and run over it, then replace it with an OEM type.
Also, tire pressire, correct allignment, clean filters, etc. are great starters. Where are you getting this milage from. The computer or working out the numbers when you fill up? I know some cars will tell you "instant mileage" and "average mileage". I would not trust this. I would work out the numbers when I fill up. In your case neither will be accurate because of the size of your wheels and the speedometer/odometer will not be correct. JMO
Still not accurate because your wheel and tire size throw off speedometer and odometer so the milage you are using in your calculation is incorrect. Put factory wheels and tires on the car and then try the milage.
The tune up aint complete without it. Make sure the air filter is clean, and spray the MAF out with brake cleaner. Also, are you running a K&N filter? If so, throw that under the back wheel and run over it, then replace it with an OEM type.