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kavephish
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| Posted: Jan 03 2011 at 10:01pm | IP Logged
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2006 4x4 SE 4.0, 73000 miles. When I bought the truck 2 yrs ago I was getting 20mpg. Afew months ago it started drifting down to 16.5 mpg. Today, I got 50 miles out of 1/4 tank!! went from approx 325 miles per tank to (now estimated) 200 miles per tank. Truck starts and runs well, but does not seem to have quite the ooomph it did at first. I change the oil regularly. Tires are always up to max pressure. Air filter is checked regularly and is clean (not a genuine Nissan oil impregnated one - sorry Frontierguy, you can jack me up for that). The tailpipe is not sooty at all and the exhaust does not smell rich. (maybe the cats are working overtime?) anyway, the only code the IPDM has thrown in 2 years was for a faulty/leaky fuel vapour purge valve. I cleaned the unit and the code was reset. No codes since. I also cleaned off the MAF (or AMM?) with the proper cleaning spray and no change.....is it possible I have a faulty O2 sensor(s) pre cat that is not throwing a code? Any other possibilities?
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2006 Frontier SE Crew Cab 4X4
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Boomer
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| Posted: Jan 04 2011 at 5:10am | IP Logged
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Disconect the battery for 30 minutes and then restart the truck. Should allow the computer to return to original settings. See if this helps. Also, check tire pressures and remeber that winter gas will lower your mileage a bit.
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2007 Nissan Frontier SE 4X4
Crew Cab, short bed,
2003 Saturn L-300 sedan
2013 VW Passat TDI
State College, PA
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kavephish
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| Posted: Jan 04 2011 at 1:47pm | IP Logged
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disconnected the battery for 45 min or so and went for a 5 mile drive after hooking it back up. No codes......also, my initial mileage drop started to occur months ago before "winter gas" was available. thanks for the help though.
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2006 Frontier SE Crew Cab 4X4
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Boomer
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| Posted: Jan 04 2011 at 5:50pm | IP Logged
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Check your tranny fluid. Is it full? Is there evidence of anything in it? Inefficiency in the trans might be an issue. Also, is it possible your cats are clogging or disintegrating causing a lot of back pressure?
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2007 Nissan Frontier SE 4X4
Crew Cab, short bed,
2003 Saturn L-300 sedan
2013 VW Passat TDI
State College, PA
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kavephish
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| Posted: Jan 04 2011 at 6:00pm | IP Logged
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Tranny fluid is right at the top of the "hot" mark (engine hot) and is crystal clear and smells good. It does not look as "candyapple red" as other T fluid I have seen though....maybe just a slightly different kind? Also, how could a shadetree mechanic check the cats? plugged cats/exhaust would account for my problems, but would not the O2 sensor post-cat pick something up? (I think I read it has O2 sensors pre and postt cat)
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frontierguy
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| Posted: Jan 04 2011 at 6:25pm | IP Logged
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The O2 sensors and cats could be getting "tired" but are
still working w/in acceptable parameters. And yes, you know
my thoughts on the Genuine Nissan air filter!!!!!!! Have
you checked the grounds on top of the left timing cover.
Adding addition ground support is always a good idea.
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'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
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kavephish
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| Posted: Jan 04 2011 at 7:59pm | IP Logged
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I checked the engine ground on the timing cover...it looked pretty clean but I sanded it off anyway and skimmed the surfaces with a little dielectric grease for good measure. Too bad my *gas allowance* isn't still within parameters at $1.16 per litre lol.
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ezramore
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| Posted: Jan 11 2011 at 8:48am | IP Logged
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Has your local gas stations changed the octain of their gas. They do that in winter here in Colorado and it always kills my milage. try an octain booster for a tank or 2 and see if it helps. They change it just before winter here so its a possibility.
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White 2009 Frontier SE crew cab with Chrome kit and Pikes Peak package (Sunroof, Off Road Package, Towing package, Mooonroof, clear bra kit)
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Stokersrule
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| Posted: Jan 11 2011 at 4:52pm | IP Logged
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I'm pretty sure dielectric grease is the opposite of what you want on your ground connection.
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frontierguy
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| Posted: Jan 19 2011 at 6:33pm | IP Logged
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What is wrong with dielectric grease on a ground????
Kavephish - we are paying $3.23/gal here in the USA for
regular.
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Nissan Frontier Forums : Problems / Technical
Topic: more gas mileage woes
