SES lights and codes on 2005 Nissan Frontier v-6 crew cab, with automatic transmission, 91K miles


#1

so. (always start with this word, right?). i bought a 2005 Frontier w 87K miles on it back in October 2015. It’s a V6; tho i don’t baby it or ease and slip around, i am finding it does not ever get better than 14 mpg. i’m not a leaden foot, but i move quickly sometimes. in mixed driving in Austin and on the freeways to the areas within 20 miles, i have to say, i’m disappointed in this gas consumption.
anyone know if there is a likely ‘tune-up’ or some way i can improve this. maybe this rig is actually just not going to do better. the specs i see tho, do show over 16mpg.
next: i’m having a weird, perhaps imagined, noise that i think i’ve traced to an aspect of the automatic transmission or the drive train in general.
when i’m clearly NOT hitting the raised bumps that in the lane marking lines on the road, which are intended to cause a fast bumpy vibrating noise as a warning . . . i seem to hear this very noise, and vibration of the vehicle, as i drive at around 50 ~ 60 mph along the road.
i was driving up the road a couple days ago, and when this vibration bumping phenom happened, i slowed down to say 40mph–and it stopped;
for no reason other than desperate instinct, i sped up again rather quickly, and i reproduced that very vibration and bumping.
i did this a couple of times, slow down, it stops; speed up the torque quickly and it starts; etc.
so i supposed i was causing this by accelerating, torquing fast, and that something in the transmission, or rear end maybe, was doing something wrong.
what the heck?
this is the first AT i’ve ever had, so i’m not aware of any such kinds of peculiar behaviors with such drive trains. maybe i’m totally off the mark.
but anyone have any ideas what this might be?
otherwise, actually, the performance and the regularity and solid action of the drive train seem all to be intact, and working right.
but that dang intermittent bump vibration thing (it’s happened at least ten times since october–always when i’m at highway speeds, like around where there are good fourlane or more lines and markers etc).
it’s giving me the jitters.
if i hear back on this, then i’ll shut up, and go on to my inquiries about the arcane SES light, that says my fuel level sensor has a voltage problem . . .
and other issues.


#2

Do you feel a vibration in the steering wheel when this noise occurs? My guess would be a wheel balance problem.

Your header says something about engine check codes. What are they? More details please.


#3

You speed up to 60, then hear the noise…take your foot off the gas, does noise stop immediately? If not, could be a bad wheel beating.


#4

Bill R. i guess i shd have put the SES stuff in a different post. it’s not related to the vibration/bumping problem. i lost the actual code nr, but it’s one that indicates a high and low voltage problem with the fuel level sensor, tht’s in the gas tank.

Anyway, on the road noise, or vehicle vibration, issue: there is NO vibration or oddities with the power steering wheel. NOne at all. and i do imagine i might have a wheel bearing issue, however it doesn’t seem to play into or contribute at all to this intermittent condition.
the vibration is exactly like what you get if you run your wheels on to the side lines, the markers with the raised bumps in them, that are intended to cause you to have bumping, to WAKE YOU UP, as a safety feature.
my problem happens when i’m NOT running onto those lines with the bumpywhumpies.
and then it goes away, in a few seconds. if it were a wheel balance problem i think it would not just stop of a sudden, when one is keeping a fixed the vehicle speed.
yes, there would be a ‘range’ of speeds when wheel balance problems would become perceptible, but that’s not what’s happening here i think.