I have replaced plugs & wires (AC), O2 ( Bosch), Fuel pump(AC-I think) and Filter(AC), Air Filter(AC) Tranny fluid/filter(AC) changed, Cam Sensor(Wells) and Crank Sensor(KEM), Timing Set(Make??) and Interuptor magnet(Wells) and finally front tires(Eagle GPS'). Car is on cruise at no more than 75 on the highway. I drive approx 50 miles round trip for work 6 days a wk. I will be getting some seafoam tomarrow. Gas isn't getting any cheaper I am just wondering If I can get more than 18MPG City/Hwy. I have done all the work to my car, so you aren't speaking to a newbie. Maybe I've just missed something. Is 18MPG normal for Series 1 N/SC???

Do you make a lot of short runs with your car? Every time you start your car up, all of the injectors dump at once. That can tend to eat up some fuel.

Varies daily anything form fast food or gorcery store runs to 30-60 mile trips. I was debating replacing the injectors but i keep seeing better deals for higher psi injectors. Since I m not supercharged it kinda defeats the purpose of puting in higher pressure, doesn't it

Have you checked for leaky fuel injector(*) and/or FPR?

If I recall I had only 28psi before the pump change and about41-42psi after the change. I know the injectors have a history of leaking at high mileage. I havnt replaced theose o rings yet.

The "O" ring will only prevent an external leak. If the injector is leaking, it is doing so internally and burning unmetered fuel. You need to pull the fuel rail, have someone turn the key on (do not crank) to energize the fuel pump and pressurize the fuel system and look for a leaky injector(*).

To check the FPR, simply pull the vacuum hose while the engine is running and look for fuel leaking from the nipple, there should be none.

18 MPG ? Thats about 2 better than I'm getting. My car has been modded but I didn't expect 16 to 17 MPG'*. My two biggest gas mileage killers were the smaller pulley and the 180 thermostat. Not real sure why on the thermostat. Also, the Boost bypass mod
took away about 3 or 4 MPG'*.

I feel the pain each time I pump that 93 octane.
But, if your gonna play you gotta pay.

JLathem

i didnt know that happened

The ONLY thing that might possibly be a problem is that Bosch O2 sensor. A lot of members here have had problems with Bosch stuff. You might want to replace it with an AC-Delco unit. Unless your transporting some serious weight in your trunk I would just make sure that you're using either 10W-30 or 5W-30 motor oil and make sure your tires are inflated to around 32 PSI. You should average at least 22 mpg with the type of driving you do.

The tires are religiously checked and air added when needed. The oil is replaced every 5000 miles. I wll replace the O2 sensor and add some seafoam(oil change coming soon).