dutch300zx

Hi everyone,
My college commuter car, a 1997 Infiniti I30, isn't getting as good of MPG as I hoped for. Recently had new muffler, NGK spark plugs, air filter, fuel filter, knock sensor, and PCV valve. Running 93 octane. Had a CEL for the EGR valve, but that was cleared after the above were replaced and has stayed off in over 300 miles of driving. Per my Torque Android app, I get about 23-24 MPG highway with cruise at about 70 mph. MPG didn't seem to be affected much wether there were 2 or 4 people in car. My searching on this site seems to say that I should be able to get 28-30 MPG. From searching, it also appears that it could be a worn out front O2 sensor. What bank/sensor number is this? Is there anything else that would cause bad MPG? Thanks guys!

eddie982

iTrader: (10)

change out the O2's, clean throttle body, seafoam engine.

njmaxseltd

iTrader: (19)

Clean the EGR passage, that will probable get you up there. It's common that they clog up and restrict flow. The code will come back, the tune up can't clean that.

Aburn95

iTrader: (1)

I've recently replaced both front O2's, MAF, and seafoamed. Still getting the same MPG as you. I've never cleaned my EGR tube so I know that wouldn't hurt. I'm afraid to tackle the task. I tend to screw things up and break things every time I work on my vehicles.

I'm also having misfire and hard start issue and I'm sure whatever's causing those problems isn't helping.

It also has a brand new fuel filter and my plugs are less than a year old. Air filter not that old.

JvG

You might consider cleaning your MAF. A company called CRC markets a chemical that you spray on the wires in the MAF. It is a spray can. called Mass Air Flow sensor cleaner. Mine runs better and has better mileage. I had not cleaned it since I bought the car 85k miles ago. What a difference>>>>