I finally changed my spark plugs; I have 126,000 miles on the car and today I replaced the original spark plugs with Bosch Platinum 2 plugs. The car had been driving great but I started to notice a decline in gas milage (approx. 16.2 mpg/city), thus the change (I know it was overdue). This car has really been problem free and I want to keep it that way; going to start taking better care of it. Can you guys think of anything else I might need to do to increase fuel efficiency? TALK TO ME.

 

NGK platinum or up are the best sparks for Maximas. Maximas don't handle twin spark or higher plugs, especially those Bosch plugs. Stick with NGK!

 

Well, I've already installed the Bosch plugs; so far no problem, seems to be running fine. I'll keep an eye on it and monitor performance/gas mileage and if I'm dissatified I'll return them to Bosch (money back guarantee).
Thx for the reply; the plugs I removed were NKG and yes they served me well for 126,000 miles, probably should have gone with them again but we'll see how it goes. Again, thx

 

1. Have you replaced fuel filter lately?
2. How about PC Valve?
3. Have you cleaned the throttle body?
4. Have you considered a good quality free flow air filter?
5. Synthetic oils such as AMSOIL 0W-30 have been proven to increase milage.
6. Get some NGK Laser Platinums to replace the Bosch as they are a misapplication. Only required if you want optimum performance and milage!!!! Of course anything might be an improvement over plugs with 126,000 miles on them.
7. Have you cleaned IAC lately?
8. I keep my tires at 33 lbs.
9. Every 3,000 miles or oil change I use fuel system cleaner (Chevron).
10. I use 93 Octane gas for optimum performance and milage. Chevron is brand of choice but use Exxon as second choice.

 

What is IAC? Where does it located? Any procedure online to clean it?

BYW, my Max says 32/29psi front/rear. Do you put same on all four corners?

 

There is a good right up on IAC, that is how I found out about it. You can find it using search. Yes I keep 33 LBS in all four tires - it is easier for me to remember.
Be well!!!!

 

So you had your original plugs in there for twice their lifespan? Wow.

Don't mean to scare you, but with the Bosch +4s, what good is a money back garrauntee if you take them out and find that the electrodes had broken off and fallen into the motor?? That has actually happened to one user on here. Maybe the tech who put in the plugs simply torqued them down waaaaaay to much. But still, never had any stories like that concerning NGKs.

DW

DW

 

I am using the Bosch Platinum 2 plugs and they are working great so far. But I hear ya on the NGK's, which after 126,000 on one set I can say they worked great!

 

IM on 152k miles and still havent changed the spark plugs, gas mileage is getting worse and worse. Guess its time..

 

Ditto

 

in addition to karguy's post, worn spring/shocks will decrease your mileage, also.

 

oh great

 

My buddies I30 was a victum of Boash +4 plugs. It only took 15K miles to EAT THEM UP. The car started to have very hard starts and poor gas mileage until the day it wouldn't start again. When we pull the plugs out there was absolutely no electrode left. I never saw anything like that before.

Save yourself some aggravation down the road, take the Bosch plugs out, return them and get your money back. Just say you weren't satisfied. That's their guarantee!