2008 2.5L Spark plug help...Horrible gas mileage issue.

[nissan owner1]

Newbie...

I need help with changing the spark plugs, from my understanding the socket needed is just a standard 5/8 spark plug socket, but once I drop it in, nothing...Its too big, are you guys requiring a special size socket, or is just a smaller socket. I don't feel like experimenting on it with other sockets.

Also I did research a little but I couldn't find anything specific, just how the V6's are hard to swap.

Mine is a L4
92k miles - 2008 Altima 2.5S

The main reason I am wanting to swap them, is because I am getting horrible gas mileage. It is currently 24.3 mpg average based of the gauge, back at 80k, 70k and 60k miles I was getting 32 mpg average constantly, with the same route, same driving style, same maintenance performed on time. Yes I checked tire pressure, again air filter always replaced at least at 8k. I am using 5/30w oil synthetic, and weather wise it has been kinda of cooler it, but I live in Southern California so its not that crazy.

I was thinking that it might be the spark plugs, if that doesn't help the fuel filter is next. I have never changed that. Don't know when that is suppose to be changed.

Any help or tips that you guys can provide me with would be awesome. Thanks.

[nissan owner1]

Found my spark plug answer...In case someone comes up with this question for the spark plug in the future here is the link to the answer.

http://www.nissanclub.com/forums/2007-n ... hange.html

[nissan owner1]

Any tips on the gas mileage?

[QR25DE]

1. How are you calculating the gas mileage? Are you using the display on the cluster or actually calculating it with the trip meter etc.

I don't think spark plugs would affect your gas mileage that drastically. That's such a big change. I would suggest relearning/resetting the ECU first.

You can do this by doing the following:

1. Disconnect the battery for 10 minutes. Reconnect it.

OR

2. Put car into ON position (do not start the car) with the driver's side door open.
2a. Press the rubbery door latch switch 7+ times quickly right after you put the car into the ON position.

If done correctly, the wipers may go on and the lights will flash. Your ECU should now be reset.

Start the car and let it idle for 10 minutes to relearn. Go for a normal drive. Not flooring it for about 10 minutes. Done.

See if this helps.

[atlM35]

On top of the ecu relearn:
New plugs, New/Clean air filter, clean injectors, clean maf, and fuel friendly driving habits all contribute to good gas mileage.