betaRepeating
Member
I have a 2004 VW Jetta Wagon TDI (I believe this is the MK4 PD engine). There are about 130,000 miles on the car. The car was given to me by my parents a few years back as I finished up college. For the most part I have driven it only on long trips to and from college (roughly 2 hour highway drive). Recently, I have been using it primarily to commute to work (roughly 10 minutes highway drive).
I have been fairly careful to chart and record the mileage of the car. Attached is a graph of my mileage over the past two years or so.
At my last fill up I measured a MPG of nearly 35 miles per gallon. I am very concerned at the apparent huge drop in the mileage of the car. Does anyone have any insight as to why this might be?
Some more details:
I consider my driving habits to be decent, if anything they have become more conservative over the last 6 months or so. I have been reading information on hypermiling, coasting more to lights and trying to be more mindful of my efficiency. I wouldn't characterize my driving style as aggressive, though I do drive fast (80mph average on the turnpike for the aforementioned commutes to and from college). My dad tells me he used to average 44-48mpg with the car when they first purchased it used from the dealer.
I purchased Power Service +Cetane Boost Diesel Kleen Fuel Additive in August of 2014 and have been pouring random amounts into my tank when I remember to do so. I haven't measured the amounts but it's been roughly 8oz per tank. I am almost out of the first bottle and I'm about to start on my second one.
My last tank (the one that got me 35mpg) was about 50% biodiesel, from some small supplier near me. I also added some diesel kleen and then some water-removing additive (I think the name had Dr in it, I can look at the bottle when I get home tonight). I have read that biodiesel is less energy dense fuel, so perhaps this caused the dramatic MPG drop? Nonetheless this doesn't seem to explain the constant downward trend.
I change the oil with some regularity and I have checked my tire pressure recently and it is fine. It has been in the shop twice in the past two years. The first time I hit a pothole with a huge chunk of asphault in it. This was in the winter, around December of 2013. I lost power steering and my engine stalled out, so I limped it into a parking lot and had it towed. The damage was a busted oil pan, and some steering damage which was corrected. In November of 2014 I was struck from the side by a car while turning, just behind the gas cap on the passenger side. The car was ruled a total-off by insurance, but I liked the car so much I bought the salvage title back from the insurance company and paid out of pocket to have the repairs done at a local body shop. He pulled all the dents and replaced a few rear panels, and had to do some work with the rear axle to get everything driveable again. Other than oil and a timing belt replacement at 110k miles, I have performed zero service or maintenance on the car.
Any thoughts as to why my fuel economy is dropping so much? It's frustrating to deal with and really starting to bother me. I've always been proud to be hitting 44+ MPG but now I'm worried that something may be wrong . Thanks for your time.
I have been fairly careful to chart and record the mileage of the car. Attached is a graph of my mileage over the past two years or so.
At my last fill up I measured a MPG of nearly 35 miles per gallon. I am very concerned at the apparent huge drop in the mileage of the car. Does anyone have any insight as to why this might be?
Some more details:
I consider my driving habits to be decent, if anything they have become more conservative over the last 6 months or so. I have been reading information on hypermiling, coasting more to lights and trying to be more mindful of my efficiency. I wouldn't characterize my driving style as aggressive, though I do drive fast (80mph average on the turnpike for the aforementioned commutes to and from college). My dad tells me he used to average 44-48mpg with the car when they first purchased it used from the dealer.
I purchased Power Service +Cetane Boost Diesel Kleen Fuel Additive in August of 2014 and have been pouring random amounts into my tank when I remember to do so. I haven't measured the amounts but it's been roughly 8oz per tank. I am almost out of the first bottle and I'm about to start on my second one.
My last tank (the one that got me 35mpg) was about 50% biodiesel, from some small supplier near me. I also added some diesel kleen and then some water-removing additive (I think the name had Dr in it, I can look at the bottle when I get home tonight). I have read that biodiesel is less energy dense fuel, so perhaps this caused the dramatic MPG drop? Nonetheless this doesn't seem to explain the constant downward trend.
I change the oil with some regularity and I have checked my tire pressure recently and it is fine. It has been in the shop twice in the past two years. The first time I hit a pothole with a huge chunk of asphault in it. This was in the winter, around December of 2013. I lost power steering and my engine stalled out, so I limped it into a parking lot and had it towed. The damage was a busted oil pan, and some steering damage which was corrected. In November of 2014 I was struck from the side by a car while turning, just behind the gas cap on the passenger side. The car was ruled a total-off by insurance, but I liked the car so much I bought the salvage title back from the insurance company and paid out of pocket to have the repairs done at a local body shop. He pulled all the dents and replaced a few rear panels, and had to do some work with the rear axle to get everything driveable again. Other than oil and a timing belt replacement at 110k miles, I have performed zero service or maintenance on the car.
Any thoughts as to why my fuel economy is dropping so much? It's frustrating to deal with and really starting to bother me. I've always been proud to be hitting 44+ MPG but now I'm worried that something may be wrong . Thanks for your time.
