So Ive been noticing that my fuel consumption is seeming pretty bad since when I first purchased the car before any modifications have been performed. I used to get about 260 miles to a tank but now im lucky if i even get about 200 miles to the tank. I did a OBDI conversion and am thinking that may be contributing to my problem. I did a lt4 cam kit swap and all the bolt ons, what else things could make fuel economy bad besides spark plugs, i have a rebuilt opti as well. Oh and i was wondering on OBDI cars the O2 sensors are before the cats or after the cats?

 

I would think your going to get worse mileage with mods to make the car faster. Having a dead on tune and everything running right would help and if your in need of a tuneup it will drop some. My O2's are in the Y pipe before the cat. With the cost of gas i get more concerned and notice the gas gauge way more. I actually drive more conservative now but as long as it stabilizes around $3 i will go back to the heavy foot.

 

yeah thats why im concerned cause gas right now in california is about $3.90 a gallon for premium and $3.50 for regular. im considering getting a 4 banger for my commutes.

 

You cannot judge gas miles "by the tank". Too many variables and not accurate. Use MPG by dividing miles by gallons used.

 

x2 This will give the most accurate depiction of how much gas you use.

 

Like he said. Could be issues with the gauge/sending unit ...

 

Use your trip meter. When you fill up, divide miles driven by gallons purchased.

 

But that said, my car gets around 12-13 city, and 24-45ish highway. I never really triued driving conservatively with the Camaro though lol.

 

My 355, ported heads, intake, lt4 hotcam 30# injectors with 3.73s I was luck to get 250 KM (not miles) to a 60liter tank!

Now im gonna have my 383 in this weekend...that should be fun lol

Jay

 

well, it really depends on how you're driving it. I used to get around 200 miles on just straight city miles, which put me roughly around 15 mpg. My average driving is around 22 mpg, highway is about 27. The tune definately helped my set up, not that its crazy extreme or anything, but I noticed a difference.