Hi, been following the site for some time. This is my first post to this forum. I need some advice from the community on the issue I'm currently having with my 05 Highlander V6. My car has about 45k in the 5 years that I have owned it. I've kept it maintained with oil changes every 3500k and changed the fluids at the correct intervals since I've owned it. I drive the car very softly and do not have a heavy foot.
The problem I have noticed in the past 3-4 months is that the fuel economy has dipped significantly. I use to average about 22 mpg, but am now only getting 15mpg. I drive a mix of highway and local traffic. I figured that I would take the car into the local toyota dealership to have them try to diagnose the problem.
Upon speaking with the service reps after they had examined the car, they informed me that I was in need of a major tune up, which included, New battery, Spark plugs, Pcv valve, emission cleaning, and the regular oil change. I figured that the car was due for a tune up anyway, so I told them to go ahead with it thinking that it was the reason for the lost fuel economy. After the service was done, the dealership provided a fuel consumption test that showed that my vehicle was running well and was getting 33mpg on average. Upon looking at the report, I found that to be unrealistic considering my car is only rated to get 24mpg highway. So, I left the dealership thinking that the problem was fixed and that it was just a matter of the tune up.
I have been driving the car for a few days now and the fuel economy has NOT improved from the tune up. I am still only getting 15mpg. I must say that the car has improved in performance subsequent to the tune up though...which i must say is quite confusing. I know that cars get lower fuel economy as they get older and with mileage, but my car only has 45k.
My question is, what other causes might there be for the poor fuel economy? Any thought or comments would be greatly appreciated.
Reply 1 : 2005 Highlander poor fuel economy
Also worth mentioning is that I recently swapped out the regular air filter with a TRD air filter. I thought that with the better efficiency, it would improve mpg.
Tire pressure is at the correct range and I have not received any check engine lights.
Reply 2 : 2005 Highlander poor fuel economy
Was this a gradual loss of mileage, or something that happened over a short period of time. Running non-OEM size tires? Dirty throttle body and/or MAF? Winter blend gas (with higher ethanol content)?
Reply 3 : 2005 Highlander poor fuel economy
Sounds familiar. Having the same problems here in Toronto. Going in for a maintenance check soon. Will probably have the carb cleaned and check hoses. Hoping for more mpgs or kpls. Air filter too. I will let you know if anything changes.
Reply 4 : 2005 Highlander poor fuel economy
I always thought it was stupid to make fuel out of food (E10 ethanol), and I saw a very noticeable decrease in my 05 HL V-6. Went from an easy 24mpg highway (rated) to barely 22. Now the politico idiots are gonna mandate E15 and make matters even worse. Fools! How are we saving gas if we use more of it? And now the farmers are on the government nipple and want to continue selling corn for fuel. Oh brother! Most of the stuff you had done to your HL would not affect mileage much. Even the plugs (which are irridium from Toyota) would not really be that worn at 45k miles. I would change gas brand. Try to change to a "tier 1" brand (major brand) and see what happens. A throttle body cleaning might help idle quality and throttle response, but I don't think it would dramatically increase mileage. I would also try to pull codes and see if there are any set in the OBD2 computer. I would also want to know what my air/fuel ratio is, to see if there's a rich condition. A good shop can check this with a good code checker tool that has runtime readouts. I have about the same mileage on my 05 V6 as you, but I average about 16-17 around town and about 22-23 on highway. Try a can of Techron fuel injection cleaner and see if this helps anything, but I probably would not expect a huge change.
Reply 5 : 2005 Highlander poor fuel economy
Looks like moving to a non-ethanol mandated state is the only option. Nevada here I come.....
Reply 6 : 2005 Highlander poor fuel economy
Quote:
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Originally Posted by Highlanderdude 
05 Highlander V6. - 45k
Upon speaking with the service reps after they had examined the car, they informed me that I was in need of a major tune up, which included, New battery, Spark plugs, Pcv valve, emission cleaning, and the regular oil change. Any thought or comments would be greatly appreciated. |
Sounds to me that the service writer at Toyota were most interested in "tuning" your wallet. There is no way your car needed plugs at 45k miles. I am not sure what emissive cleaning is either - sounds suspicious.
I had a bone stock 06 v6 Highlander 2 wheel drive and we reliably got 19 city and about 24 hwy with no problem at all. Now we have a 07 HL Limited 2 wheel drive and it reliably gets 18 city and about 23 hwy. Likely because it a little heavier with extra options, bigger wheels (18s) and tires and airbags. Note we are not fast or aggressive drivers so we drive these cars very very easy - speed limit in our town is 30 mph with lots of speed traps.
In terms of gas mileage - to maximize basic mpg - First off is drive the car like it had an egg shell on the gas pedal and avoid hitting brakes hard, careful, smooth, non aggressive gentle driving style can make huge difference in mpg. In terms of mechanical. I suggest you go back to a stock Toyota OEM air filter (just to see if there is a change). Something had to change to reduce your mpg that dramatically. Also run a couple of cans of Techron concentrate thru the gas. Switch to a teir 1 gas provider (Google Teir 1) to find brands in your area. Make sure your tires are properly inflated. Make sure your wheels spin freely and easily and that your brakes (pads, calipers) are not dragging. Make sure MAF and TB are clean. Switch to a synthetic motor oil to lower engine friction. Take off roof rack cross bars if you don't regularly use them. Take out any extra heavy stuff you might be carrying in the car. Go thru engine compartment carefully to check all hoses are on fittings tight without missing clamps and that hoses have no cracks. Make sure coolant and termistat are running correct temp. Too low coolant temp can affect mpg. I assume if the trans was slipping you would have noticed but its worth thinking about and checking. Turn off the AC button in cold weather unless you need it for defrost,
Reply 7 : 2005 Highlander poor fuel economy
I would probably lean toward an emission related component - possible a lazy O2 sensor, etc. Either an emission test or a scan/diagnostic check of the engine electronics may point you in the right direction. A dirty air filter (changed) or poor spray pattern from the fuel injectors will also affect you over-all gas mileage.
Reply 8 : 2005 Highlander poor fuel economy
Thanks for the feedback. Since my last post, I've been to my dealership for the third time now to have them try to figure out the problem. My frustration level after this third trip is to the roof. After this time, I will be writing a complaint letter to Toyota directly and filing a case with BBB. Here's a overall recap/review of what has been going on since the very beginning:
First trip in January 2011: Brought my vehicle to the dealership primarily for the nationwide Highlander Brake recall. Also brought up the issue that my vehicle was getting very poor mpg. On average, according to my calculations, 15mpg avg(driving 50/50 b/t local and highway. They took their own fuel efficency test which showed 33mpg(granted, they only tested it for 7 seconds according to the printout) How accurate can that be?! Also informed me that the cold weather has some influence with poor mpg due to the engine running rich durin warmup. The conclusion at that point- replace battery, clean emmission system, replace spark plugs, and pcv valve. I went ahead with their recommendations hoping for the best.
Second trip in early February: I voiced concern to the Toyota dealership that the vehicle was still not getting the correct mpg. The dealership informed me that I should give it some more time. Their fuel consumption test showed that the vehicle was getting correct mileage. The conclusion at this point: Dealership reset my ECU to see if that would correct the problems. It did not make any difference.
Third trip last week: I voiced concern again that the vehicle was not getting the correct mpg. Also, i would like to add that prior to visiting the dealership, I had purchased the Scan Gauge II diagnostic tool to determine a more accurate figure of the actual mpg, Throttle position, Average mpg, and check engine codes) Here are the results:
Average MPG: 14 mpg on the tank
TPS: 16-17 during idle
No check codes
What I did notice using this tool was that I was getting really poor mpg in city traffic, which consist of the usual accelerating and stopping at red lights, stop signs, and the ocassional traffic. I don't sit in traffic for hours or leave it in idle for long periods. On city roads, I am only getting average of 12 mpg.
Whereas, on highway road, I am getting very normal mpg which is 23-24.
So at Toyota, I requested another fuel consumption test be done going on local roads only. I specifically asked for them to do this since I had noticed poor mpg on local using the scan gauge. They did not do it. When they re-examined my car and did the test again, they only drove it at highway speeds. Toyota service rep informed me that they have a system/procedure of how to drive it during the fuel consumption test. The test yielded 22 mpg average going a average speed of 55mph(highway speed)
The conclusion at this point- they adjusted the idle timing and reset my ecu again. Again, no help or change to the mpg at this point.
I'm no expert, but I do think that the problem lies with the car either in idle or with the accelerating and stopping driving at stop signs and red lights. I plan to bring a formal complaint with Toyota corporate offices and see what they can do for me. Based on what you have stated, I don't think I needed all the work on the car the first time.
Reply 9 : 2005 Highlander poor fuel economy
Quote:
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Originally Posted by jabberwock
Sounds to me that the service writer at Toyota were most interested in "tuning" your wallet. There is no way your car needed plugs at 45k miles. I am not sure what emissive cleaning is either - sounds suspicious.
I had a bone stock 06 v6 Highlander 2 wheel drive and we reliably got 19 city and about 24 hwy with no problem at all. Now we have a 07 HL Limited 2 wheel drive and it reliably gets 18 city and about 23 hwy. Likely because it a little heavier with extra options, bigger wheels (18s) and tires and airbags. Note we are not fast or aggressive drivers so we drive these cars very very easy - speed limit in our town is 30 mph with lots of speed traps. In terms of gas mileage - to maximize basic mpg - First off is drive the car like it had an egg shell on the gas pedal and avoid hitting brakes hard, careful, smooth, non aggressive gentle driving style can make huge difference in mpg. In terms of mechanical. I suggest you go back to a stock Toyota OEM air filter (just to see if there is a change). Something had to change to reduce your mpg that dramatically. Also run a couple of cans of Techron concentrate thru the gas. Switch to a teir 1 gas provider (Google Teir 1) to find brands in your area. Make sure your tires are properly inflated. Make sure your wheels spin freely and easily and that your brakes (pads, calipers) are not dragging. Make sure MAF and TB are clean. Switch to a synthetic motor oil to lower engine friction. Take off roof rack cross bars if you don't regularly use them. Take out any extra heavy stuff you might be carrying in the car. Go thru engine compartment carefully to check all hoses are on fittings tight without missing clamps and that hoses have no cracks. Make sure coolant and termistat are running correct temp. Too low coolant temp can affect mpg. I assume if the trans was slipping you would have noticed but its worth thinking about and checking. Turn off the AC button in cold weather unless you need it for defrost, |
I will try running the fuel injection cleaners to see if that makes a difference. I've checked over and tried all the items that you mentioned with no difference. I have a feeling it is the O2 or MAF sensor, but my vehicle is not showing any check engine codes. I think if there was something wrong with those two, I would think the computer recgonize the malfunction? Maybe I'm wrong.
Reply 10 : 2005 Highlander poor fuel economy
When I sold Insurance door to door.. I drove a specific route. My area was no more than 9 square miles but I would drive 25-30 miles within those 9 square miles.. with low speeds and lots of idling.. especially with the A/C.. I was averaging 13mpg. Since switching back to a normal 9-5 job I travel 80/20 interstate/highway and average 19.7
The Highlander does not seem to like low speed and tons of idling so if you drive in lots of traffic.. It just guzzles the gas (from personal experience)
Reply 11 : 2005 Highlander poor fuel economy
Quote:
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Originally Posted by Highlanderdude
jabberwock,
I will try running the fuel injection cleaners to see if that makes a difference. I've checked over and tried all the items that you mentioned with no difference. I have a feeling it is the O2 or MAF sensor, but my vehicle is not showing any check engine codes. I think if there was something wrong with those two, I would think the computer recgonize the malfunction? Maybe I'm wrong. |
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