vtchris Posted December 23, 2010 Share Posted December 23, 2010 I used to average 13.5 mpg and now only get 11 mpg......my driving habits and locations haven't changed, same load, same tires with same air pressure. The 6 cyl engine has 107K miles on it, I just had the original distributor cap and wires changed, the gas tank flushed and filtered, cleaned everything. I am thinking of getting a compression test done, is that a good idea? Any other ideas? Quote Link to comment Share on other sites More sharing options...
bufbooth Posted December 24, 2010 Share Posted December 24, 2010 Hello, It could be the gasoline you are using if it has ethanol in it. Try a tank of ethanol free gasoline and see if your 13mpg returns. Also, have you changed your engine AIR filter recently, a dirty filter could account for up to a 20% mpg reduction. Later, Dennis... Quote Link to comment Share on other sites More sharing options...
vtchris Posted December 24, 2010 Author Share Posted December 24, 2010 Air filter is one of those kind that you clean instead of replace and it was cleaned recently. I can't find ethanol free gas here in S. Texas, or hardly anywhere. Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted December 25, 2010 Share Posted December 25, 2010 Might be time for a valve adjustment. Good chance it has never had one. I think 60,000 miles is the magic number. 85,000 miles is the magic number for replacing the timing belt. Also throw in some injector cleaner with the next tank of gas. Clean injectors really make a difference. Quote Link to comment Share on other sites More sharing options...
waiter Posted December 25, 2010 Share Posted December 25, 2010 Outside Air Temperature - Cold air can impact Fuel economy, especially during the initial warm-up time for EFI engines. (EFI will run richer until the engine gets up to Operating Temperature) John Mc 88 Dolphin 4 auto Quote Link to comment Share on other sites More sharing options...
vtchris Posted December 27, 2010 Author Share Posted December 27, 2010 I know for a fact that it has never had a valve job. How expensive are they? Isn't that what a compression test will show me? Can any mechanic do it or should I go to the Toyota dealer? Any particular brand of injector cleaner I should get? Quote Link to comment Share on other sites More sharing options...
Nam Posted December 27, 2010 Share Posted December 27, 2010 I use Cheveron Techron for injector cleaner (the box that you can get at Costco for a decent $). I don't think compression test can tell if you need valve clearance adj. or not. A reputable mechanic can do the job. I will attempt to do mine soon. My Warrior 319RB avg. 14MPG and I thought that was bad enough. BTW, are you using those K&N air filter? I know for a fact that it has never had a valve job. How expensive are they? Isn't that what a compression test will show me? Can any mechanic do it or should I go to the Toyota dealer? Any particular brand of injector cleaner I should get? Quote Link to comment Share on other sites More sharing options...
vtchris Posted December 29, 2010 Author Share Posted December 29, 2010 Yes, I am using the K&N air filter. Is that bad? Also when my odometer rolled over to 100K, the CEL came on.....three different mechanics can't tell me why, code says oxygen sensor which I guess covers a lot. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted December 29, 2010 Share Posted December 29, 2010 Generally the CEL code for the O2 sensor means it needs to be changed. I think you're asking the wrong mechanics and I wouldn't ask them to adjust the valves. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted February 18, 2011 Share Posted February 18, 2011 Yes, I am using the K&N air filter. Is that bad? Also when my odometer rolled over to 100K, the CEL came on.....three different mechanics can't tell me why, code says oxygen sensor which I guess covers a lot. Having the valves adjusted with a new timing belt for high mileage engines is a good idea - this engine uses shims so it is pretty hard to DIY. I am having similar mileage (93 Winnie warrior). I had an intermittent CEL - never got a code out of it. Took to a shop that hooked up a OBD1 reader & the it went into full rich mode and was spitting unburned fuel out the tailpipe. The threw a mass air flow sensor at it and that solved the "new" problem. I reset the timing and the fuel mileage seemed to improve for a while but now it is back to 12. Like before , the exhaust smells a bit rich. The engine runs strong with only a slight rough idle. The local toyota dealer says for 1 hour labor max ($100) they can diagnose it. I am guessing you have a problem similiar to mine -- and it will end up being a ECU related item like an oxy sensor. If your oxy sensor is bad I think that is easy to verify with the right equipment. Quote Link to comment Share on other sites More sharing options...
waiter Posted February 19, 2011 Share Posted February 19, 2011 Running Rich. If your not going into closed loop (faulty O2 Sensor), the engine is running on a program mode which is a little rich. ALSO, If the thremostat is sticking and not allowing the engine to come up to temperture, ECU will not enter closed loop. Dirty fuel injectors with bad pattern or leaking will cause high fuel consumption. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted September 30, 2011 Share Posted September 30, 2011 UPDATE: toyota dealer could not diagnosis so they finally tried an O2 sensor - now I get 13 mph & no performance issues. i had heard O2 sensors "wear out" - with various life expectancy -- if I had to do it over again I would change that first. Mine cost about $110 at the dealer (I think that was their cost as they already were into me about $500). Advance & Autozone had comparable pricing. ***************************** Having the valves adjusted with a new timing belt for high mileage engines is a good idea - this engine uses shims so it is pretty hard to DIY. I am having similar mileage (93 Winnie warrior). I had an intermittent CEL - never got a code out of it. Took to a shop that hooked up a OBD1 reader & the it went into full rich mode and was spitting unburned fuel out the tailpipe. The threw a mass air flow sensor at it and that solved the "new" problem. I reset the timing and the fuel mileage seemed to improve for a while but now it is back to 12. Like before , the exhaust smells a bit rich. The engine runs strong with only a slight rough idle. The local toyota dealer says for 1 hour labor max ($100) they can diagnose it. I am guessing you have a problem similiar to mine -- and it will end up being a ECU related item like an oxy sensor. If your oxy sensor is bad I think that is easy to verify with the right equipment. Quote Link to comment Share on other sites More sharing options...
Boots Posted April 6, 2012 Share Posted April 6, 2012 Hi, I am assuming you are driving at the same altitude, but if you are not that might explain. I have a 92 Winnepago with the V6 and I get 24 - 28 mpg. So I don't know what the difference is other than weight, location or perhaps the computer. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted April 6, 2012 Share Posted April 6, 2012 Hi, I am assuming you are driving at the same altitude, but if you are not that might explain. I have a 92 Winnepago with the V6 and I get 24 - 28 mpg. So I don't know what the difference is other than weight, location or perhaps the computer. Are you really claiming 24-28???? I think your math/ methods of computing have to be way off ---- I have had 2 of the V6's and from everyone I met over my 20k miles of travel also indicated they get 14-15 Quote Link to comment Share on other sites More sharing options...
guitarlover519 Posted April 10, 2012 Share Posted April 10, 2012 24-28? That would be nice haha defiantly impossible, considering the Camry doesnt do too much better than that. Hi, I am assuming you are driving at the same altitude, but if you are not that might explain. I have a 92 Winnepago with the V6 and I get 24 - 28 mpg. So I don't know what the difference is other than weight, location or perhaps the computer. Quote Link to comment Share on other sites More sharing options...
waiter Posted April 10, 2012 Share Posted April 10, 2012 Hey - My 97 Camry with 260,000 on it gets 26 in town and 33 on the road. I'm not sure if a toyhouse will get 25 mpg even at the very low speed end, i.e. 35mph. The best I've ever see with mine is almost 18mpg, and that was with a good tail wind heading eastbound on I-80 through Wyoming (High altitude always does a little better) John Mc 88 Dolphin 4 Auto Quote Link to comment Share on other sites More sharing options...
Totem Posted April 12, 2012 Share Posted April 12, 2012 the o2 sensor will impact fuel consumption... can't believe no one suggested that. depending on the report back from the sensor extra fuel will be dumped to help catalytic conversion. Dead sensor makes her run rich always. 7 k on a dead sensor is 7 k of rich runnings. They do make sensor fakers that keep fuel mixture prime for best economy regardless of exhaust; nice little diode set that wires in where the sensor used to. Most states don't make 80's vehicles pass emissions. o2 sensor $60-$120... mileage based in large part on exhaust, need replaced 100k. faker $10-20 perfect mileage, outlast engine Quote Link to comment Share on other sites More sharing options...
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