I have 93 Maxima SE (auto) with only 70K miles. I am pi**ed of with mileage I get from my car now a days. I used to get get 300 miles for 13.5 gallons i.e close to 22 MPG... That too on city driving..
Now I am getting only 240 for 13.5 Gallons.. i.e 17 Mpg..
I replaced
- PCV valve
- O2 sensor a week ago.

- Spark plugs
- Fuel filter
- Fuel pump were replaced at 60K service..

I have cleaned throttle body, IAC valve.. I have also checked Coils, Injectors (for resistance).

It runs well. But I don't understand the reason for less mileage.. Is there any thing else I can look at..?
I know vaccum leak could be an issue. How do I check..?

Appreciate your expert opinion..
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have you changed your driving style to be more agressive?
tires inflated properly?
air filter clean?
changed brang of gas or maybe the gas is a different mixture or additives?

I figure you did this stuff already and they probably wouldn't account for how bad the mileage has gotten, but they could be contributing to the mess

 

exhaust leak! if you have an exhaust leak gas mileage will drop a lot. my y-pipe is leaking real bad and i lost 100 miles to the tank (about 400 miles per tank normally now 300) and my power SUCKS now.

 

I got new tires and they are inflated properly. I forgot to mention that I have new air filter (genuine nissan)
I use 93 octane gas..
Driving style not much of change... But it has been mostly city driving..

Now for city driving what is the best mpg I can expect from 1993 Nissan maxima SE ?

 

this is going to sound kinda stupid, but how can i check to see if i have an exaust leak, and WHY would it cause loss of power / milage


Chris