96' Maxima giving more miles/gallon after driving on highway

[sanchalanam]

Hi All,

This year in Jan, I purchased a Used 96' Maxima (overall milage120 K) from a Nissan Dealer. I am using this car for daily commute to my office, 4 miles from my residence. It used to give me 16-17 Miles/Gallon mileage. Recently, I traveled to NewJersey from Virginia (2 * 260 miles) and since then mileage increased from 16 miles to 24 miles per Gallon (inside city) and 30 miles / gallon on highways.

I haven’t noticed any difference in performance.

But, I am still worried and desperate to know the reason for the sudden change in mileage/gallon. Please let me know if someone experienced the same with his/her car.

Should I take the car to a mechanic? Please advice.

Thanks,

Sanchi

[sanchalanam]

Please give an advice.

[Ceasars Chariot]

do you have a check engine light ? if so have the codes check and go from there

[Jetts]

isnt better gas mileage good?
your car was probally just pissed you drove it 4 miles everyday and the drive to jersey cleaned out the system
did you do any matenice shit to it before you left for jersey?

[BP2K2Max]

Originally Posted by Jetts

isnt better gas mileage good?
your car was probally just pissed you drove it 4 miles everyday and the drive to jersey cleaned out the system
did you do any matenice shit to it before you left for jersey?

that's what i would say. maybe your fuel lines/injectors were clogged and got flushed out over the course of the journey.

[sanchalanam]

Hi All,
Thanks for your replies.

Now, since yesterday, Check Engine light is on.
What do you suggest? Is there any problem with the engine? Fuel consumption is never consistent. Sometime it gives 22 MPG and sometime 18 MPG (both inside city).
However I decided to get the engine checked with the computerized system (cost $87 ).What do you suggest? Should I get this done or can I make minor tests myself?

Please advice.

Thanks,
Sanchi

[BP2K2Max]

if you have Autozone stores, they'll run a diagnostic test for free. it could be a lot of different things. a new fuel filter, which would be easy. new 02 sensors, injectors, coilpack.

[sanchalanam]

Hi BP2K2Max,

Thanks so much for the info. I will check with the AutoZone.

I have one more question. Is there any quick method to check Oil Filter myself?

Thanks,
Sanchi

[sanchalanam]

Diagnostic report at AutoZone reveals 3 problems in the car, P0600,p0150,p0130.
Staff at AutoZone suggested me to change O2 sensor 1 in bank2 and bank 1.
They could not describe the troubleshoot code p0600.

Following are my observations since the Service Engine Light is ON:
1) I didn’t notice any performance difference in my car.
2) But, surprisingly fuel consumption has reduced drastically( 15-18 MPG in the past and now it gives more than 22-24 MPG)
I am driving the car very slow since the service engine light is on. But, already I traveled 150 Miles. Is it not good to drive a Car with the above mentioned problems?

Is there any easy method to find out the actual problem?

Please advice. I am confused. If I take the car to a mechanic it will cost me at least $100-200 even if there is no problem in the Car.

I appreciate any response.

Thanks,
Sanchi

[gregory1041]

I have a 97 max that the check engine light came on after a trip (600 miles). I used the on-board diagnostics to find that it was an oxygen sensor running rich. I drove around with the check engine light on for a few days and then manually cleared out the error.
My best guess is that I have used the same gas station and same grade of gas for years. The sudden change in brand and grade of may have tripped the oxygen sensor to read out of it’s normal boundaries. This was about a year ago, and I have not had any problems since. Typically if you have oxygen sensor errors, and there is no loss in power or gas mileage, your car is fine, it is just the sensor going bad. Here is a link to explain how oxygen sensors work.
http://auto.howstuffworks.com/question257.htm
Just as a disclaimer, don’t clear your check engine light unless you are pretty darn sure that there are no problems.
To find the codes and use the on-board diagnostics, you can pickup the Haynes 72021 manual at your local auto parts store.
http://www.carclinicmagazine.com/p0600.html
P0600 Serial Communication Link Malfunction

[john manley]

Originally Posted by sanchalanam

Hi All,
Thanks for your replies.

Now, since yesterday, Check Engine light is on.
What do you suggest? Is there any problem with the engine? Fuel consumption is never consistent. Sometime it gives 22 MPG and sometime 18 MPG (both inside city).
However I decided to get the engine checked with the computerized system (cost $87 ).What do you suggest? Should I get this done or can I make minor tests myself?

Please advice.

Thanks,
Sanchi

Check the o2 sensor and the ignition coils

[john manley]

Check the O2 sensor and the ignition coils. P1320 on the DTC. Also look into the Mass Airflow sensor. John

[94hondaacc]

disconnect the battery to reset your computer, that will erase the codes as well as the check engine light. i think your car has 2 o2 sensors since that was the code that poped up you should have both changed, your oil filter is change everytime you get an oil change, so you dont reallyy check it you change it. Its cheap anyway. have you done any maintence to your car? if not change your spark plugs and your gas and air filter at least.