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So my wife and I have a 2004 Nissan Frontier V6 Auto with 68,000 miles on it. (already posted similar question, but this one is now a little different and updated)
We are to the point where some preventative maintenance needs to be done, but there is also a problem that I can't figure out.
While driving slowly and lightly accelerating (I notice this in parking lots) around 4-5 mph, the motor is knocking. I figured it was probably running lean, so I put 93 octane in it. That solved the problem for a while so I have run 93 octane for the last 6 months, but now the knocking is back. There are also symptoms that the truck is running rich (conflicting). For instance, we average about 14.5 mpg around town. And even after the motor warms up, the exhaust fumes are still visible, even on a warm humid day.
So I am thinking of a few possibilities.
1. Carbon build up in the fuel system. Ran a top cleaner and some fuel and oil additive. Spitted and spewed like crazy and cleaned a lot of nasty crap out. Truck runs noticeably better now (better throttle response), but still knocks. I was thinking this was the most likely since it would cause the truck to run lean, spew crap out the exhaust, and get lower mpg. No dice. Unless it will just take some miles to take effect.
2. Spark plugs? My wife had new plugs put in before we were married (14,000 miles ago) so I am thinking this is not the problem.
3. Timing issue cause the knock sensor to pre-detonate?
I kind of want to sell/trade the truck anyways, but my wife is really attached to this particular truck (it was her first truck so I know how she feels. I almost cried the day I sold my first truck). I am just trying to decide if it is worth it to chase this problem around (the computer isn't throwing any codes) to potentially either not fix it, or reveal a very expensive problem.
I am not able to work on the truck myself right now since being injured in an accident last month, so that is another concern. The truck needs new belts (not super urgent as they are just starting to crack a little on the outside), new wheel cylinders, and exchange of all fluids (neglected to do this at 60k.). Also, one of the bearings in a pulley is making some noise, so I am thinking that a pulley will need to be replaced as well (when belts done obviously). Other than that, everything is solid. Suspension, transmission, drive line, etc...
Any thoughts as to what the problem might be? What would you do? If we sold or traded the truck, whatever we got for it (probably $9k or so) would be our shopping budget as we are not interested in acquiring a car payment. Also, we don't technically need a truck, as we only use it for fishing, and any other truck/car with a roof rack will suit this need just fine. We just both like this truck as it has served us well, and are hesitant to get rid of it.
I just can't justify 14.5 mpg when we don't have to. Also can't justify $1500-2000 in repairs and maintenance. Seeing how I could do it all (except timing, I don't want to screw with that myself) for $500 or less if I were feeling better.
Thanks for any advice in advance.
We are to the point where some preventative maintenance needs to be done, but there is also a problem that I can't figure out.
While driving slowly and lightly accelerating (I notice this in parking lots) around 4-5 mph, the motor is knocking. I figured it was probably running lean, so I put 93 octane in it. That solved the problem for a while so I have run 93 octane for the last 6 months, but now the knocking is back. There are also symptoms that the truck is running rich (conflicting). For instance, we average about 14.5 mpg around town. And even after the motor warms up, the exhaust fumes are still visible, even on a warm humid day.
So I am thinking of a few possibilities.
1. Carbon build up in the fuel system. Ran a top cleaner and some fuel and oil additive. Spitted and spewed like crazy and cleaned a lot of nasty crap out. Truck runs noticeably better now (better throttle response), but still knocks. I was thinking this was the most likely since it would cause the truck to run lean, spew crap out the exhaust, and get lower mpg. No dice. Unless it will just take some miles to take effect.
2. Spark plugs? My wife had new plugs put in before we were married (14,000 miles ago) so I am thinking this is not the problem.
3. Timing issue cause the knock sensor to pre-detonate?
I kind of want to sell/trade the truck anyways, but my wife is really attached to this particular truck (it was her first truck so I know how she feels. I almost cried the day I sold my first truck). I am just trying to decide if it is worth it to chase this problem around (the computer isn't throwing any codes) to potentially either not fix it, or reveal a very expensive problem.
I am not able to work on the truck myself right now since being injured in an accident last month, so that is another concern. The truck needs new belts (not super urgent as they are just starting to crack a little on the outside), new wheel cylinders, and exchange of all fluids (neglected to do this at 60k.). Also, one of the bearings in a pulley is making some noise, so I am thinking that a pulley will need to be replaced as well (when belts done obviously). Other than that, everything is solid. Suspension, transmission, drive line, etc...
Any thoughts as to what the problem might be? What would you do? If we sold or traded the truck, whatever we got for it (probably $9k or so) would be our shopping budget as we are not interested in acquiring a car payment. Also, we don't technically need a truck, as we only use it for fishing, and any other truck/car with a roof rack will suit this need just fine. We just both like this truck as it has served us well, and are hesitant to get rid of it.
I just can't justify 14.5 mpg when we don't have to. Also can't justify $1500-2000 in repairs and maintenance. Seeing how I could do it all (except timing, I don't want to screw with that myself) for $500 or less if I were feeling better.
Thanks for any advice in advance.