Well i did some preliminary numbers on my car since i am still at half a tank. From what i can tell i am getting 9 mpg on a completely stock car minus a set of 3.55 gears and a cai. Im at a loss where to start. Thanks in advance.
pull the cel codes.. is your cel light illuminated? autozone will do it free...need more info....how is car running,skipping,smoking,strong smell of gas ect... are you in need of a tune up? first thing that comes to mind is bad o2 sensors..
no power upper rpm's 3,500 and above. sounds like the exhaust is backfiring when i get on it. plugs, wires, cap and rotor are all 1 yr old. stock o2 with 139,000 miles on it. i already ordered o2's cause that was my first thought as well. just need to know if there is anywhere else that i should be looking for. no cel
pull the cel codes.. is your cel light illuminated? autozone will do it free...need more info....how is car running,skipping,smoking,strong smell of gas ect... are you in need of a tune up? first thing that comes to mind is bad co2 sensors..
As for the milage aspect, I'd go fill it up (to the same point you did last time. Be consistant about top-offs after the pump clicks off, etc) and then calculate milage. The gauge is simply too inaccurate to interpolate the way you are trying to do.
Your other issues: You didnt use plat plugs, right?
How old is the coil? How long since a fuel filter? Can you see FP while this is occuring (cowl gauge, etc)?
If you accelerate past 3500 RPM slowly, does it still cut out or does it do better?
More info like that, along with codes, might help the smart folks on here to provide advice that might save a couple of bucks.
Good luck.
With that many miles I would consider replacing the IAT, ECT sensors along with the O2 sensors. They all work together to adjust the air/fuel mixture. Have you checked the timing setting. Advancing timing not only increases HP but also increases mileage.
Another thing to try is shifting at 2000rpm for every gear. Its a matter of changing your driving style. I went from 17-18mpg to an average of 22.5mpg just from the change in what rpm I shift the gears.
Listen to Hissin... Fill up the car and reset the trip meter... drive through a tank, repeat and calculate milage... do this a few times for a baseline.... then start looking at plugs, wires, etc...
Heck if you are only getting 9mpg it won't take long to get the tank to be empty...
For reference, on my reference only fuel gage, I get about 100-110 miles to the half tank mark, and I get 18-19 MPG depending on how I drive...