The quest for gas mileage on a 2005 Frontier

Worren · Jun 22nd, 2008, 03:14 PM

Love this truck, bought it new in '05. Stock mileage was 19.6 highway and less around town. I changed all the fluids to synthetic including the tranny. B&M makes a great synthetic trans fluid called trick shift. Put in a K&N filter system and added a few aluminum "skid" plates underneath. Hardest thing was reprogramming my right foot to take it easy. Now I make the 250 mile freeway trip to see my son and post 28.3 to 28.9 running mid grade.
Today I bought some Bosch Platinum plugs and blissfully began changing them. Drivers side was a snap. Passenger side nearest the firewall not too bad. The last one is buried under the induction system. I tried from the top, went through the fender well, every contortion I could manage. Six hourslater, in severe pain, I am here asking if anyone knows a reasonable way to change this last plug. If you stand in front of the V6 Frontier, it is the first plug on your left. All hints will be appreciated. I've never been stumped like this before.
Thanks in advance

DADEO · Jun 23rd, 2008, 04:37 PM

I have an 06.
I attempted to remove the same plug ( it's Number one )

I could not do it either.

I am sure there is a trick, just don't know what it is.

Now your fuel mileage is wonderfully better than mine.

Best I get is 19.8.

Now mine is a 4x4 and I am using regular oil.

Is that all you did, was change to synthetic to get that mileage ?

Centurion · Jun 23rd, 2008, 07:06 PM

You can remove the plenum, but i don't know if it's required but it is common to do so on many vehicles to change plugs. I've had my plenum off twice and the second time it came off in minutes and is not a daunting task at all.

Basically, it is held down with 7 bolts. The MAF and air intake have to be unbolted, as well as the plastic engine cover. The mounting bracket on the left needs to be removed (unbolted). Some wires and their bracket near the firewall has to be unbolted and pushed aside. A canister/sensor on the right, bolted to the plenum, has to be removed. I may have missed some steps, but that's about it. (You can re-use the gaskets)

HOWEVER, if you drop ANYTHING down the intake while removing the plenum or changing the plugs, you are TOTALLY screwed and if you can't fish it out then the cylinder head must come off!

Worren · Jun 24th, 2008, 06:28 AM

Thanks guys for the replies. Dadeo, other than keeping an eye on what my pedal foot was doing, the basic modification was the fluid change. Also, I keep my 16 inch tires at 42psi and filled with Nitrogen. Never mind what the door sticker says. Inflate your tires on a flat surface until there is full contact across the whole thread. If it's high in the middle add air. If the sides start to pull up take some out. A good strong light will help you with this. My tires usually last 70 to 75 thousand miles unless I run over something. A local truck shop got me to try the Nitrogen, saying the tires would run cooler. As it's hard (impossible) to check the temperature difference, I do notice that the pressure has stayed the same for over 6 months instead of leaking a pound or two a month. They charge $35.00 to fill four tires and guarantee the fill for a year.
Topside, I finally got the work lights out and unbolted the plenum. Being afraid of getting stuff inside as Centurion mentioned, I first blew all the dust and dead bees off the top of the engine and lifted the plenum just far enough to get the tools inside. The worst wasn't the spark plug wrench but rather the little screw that holds the wire module in place. They chose to place it closer to the center which made removal difficult. A quick trip to Advance Auto and I got a stud with a little bar on top that I can twist like a handle. I doubt if I'll ever change those plugs again but it's there if I need it.
Make sure you hook up all the hoses and tighten everything back up before you start up or you'll get a check engine light. I also used the opportunity to Armorall the plastic and rubber underhood. So now I have the final modification. Going on a highway trip across the state on July 4th. Will try for a mileage check then.
Thanks again for the replies.

DADEO · Jun 25th, 2008, 12:56 PM

Thanks for your reply.

I am on my second set of tires.

The first set worn in the middle at 36 psi. and only 30,000 miles.
That pressure is what is recommended.

I sell industrial gases so getting nitrogen is no problem.

I am going to try the 42 psi. and Nitrogen.

Sure can't argue with your mileage and success.

Thanks again.

Worren · Jun 26th, 2008, 05:44 AM

Let me clarify a bit Dadeo. The first step is to look at the tire where it contacts the floor. A flat, smooth finish is what you need, like a garage floor or even an auto shop floor. Shine a light from the opposide side of the thread. Go to the other side of the thread and look, if you see light in the middle, inflate the tire until it disappears. If you see that the edges aren't making full contact, remove some air. The point is to get as much of the thread in contact with the ground as possible. Every tire is not the same and the pressure needed to maintain that contact changes as the tires wear and the front end alignment ages. 42 pounds is what worked for me. It may not be what you need.