Spoke to the dealer about my poor fuel economy...

[Camry1999]

So, I gave my '05 Camry to the dealer about the very poor fuel economy. the first week after I changed the spark plugs, During the week, it seemed like I was going to get close to 27 MPG, but then when I went to get gas, I got about 25 MPG. Now, I am getting about 16 MPG, So, I gave my car to the dealer & this is what they had to say...my water pump was leaking and there is this growl coming from my engine which they said was my drive belt tensioner. They also said that I need to change the drive belt; the total for that all is $963. As far as the fuel economy is concerned; I had asked them about the laser iridium plugs & they said said that the plugs I had put in may not be the right ones. The dealer says I need Denso plugs type SK20R11 & the part # is 90080-91180; the ones I put in were NGK Laser Iridium type IFR6T11. The dealer also checked the ECU & found no current, pending or stored codes of any kind. Does anyone have any ideas as to why my fuel economy is so low?

[Shelbrain]

How long have you had the vehicle. Is it new to you? Try disconnecting the battery for 10 minutes or so this should reset the driver memory and that should allow it to relearn your driving habits. This was the advice I received from my dealer when I was having shifting issues, but it also helped my gas mileage improve. After I reset the ECU, I went really easy on the pedal and mileage has been doing well since then.

[LE05]

manual says iridium plugs, so the dealer is only partially right. you can put denso or ngk... i think denso is oem, and ngk is a quality oem style spark plug.

i plan to replace my spark plugs with the very same that you have in a couple of weeks.

i'm not sure on the fuel economy issue, but what kind of growling noise is coming from your engine? does it get louder on acceleration? you may have an exhaust leak which can cause a dip in fuel economy but not throw any codes. check your tire pressures as well.

[Camry1999]

I might try resetting the battery to see if that might work. As far as the codes, there are none. The growling only comes up @ around 1,500 RPM's & then goes away. I will check the tire pressure, these Dunlop's do tend to loose a little pressure.

[Camry1999]

They told me @ the dealer that there are different heat levels w/these plugs. I went to AutoZone & they told me that that is all b/s. These plugs are just plain better.

[carsrus]

Originally Posted by Camry1999

They told me @ the dealer that there are different heat levels w/these plugs. I went to AutoZone & they told me that that is all b/s. These plugs are just plain better.

Generally speaking OEM plugs are whats best. The engine was designed with them in mind, both mpg and power.

However, unless your using a completely diff. type of plug it wont make a huge impact on mpg.

Make sure your calculating MPG properly.

[Camry1999]

I fill up every time i go to the pump, I just simple divide the miles driven by the gallons i put in. As far as the plugs, that's what I said.

[Hillingdon]

Would not hurt to double check your work on the plug install. That is what I always do when I do a job and something does not seem right. Check that everything is installed correctly, no damage to any of the plugs, torqued correctly, make sure you did not accidentally disconnect or damage some part that was close to where you were working etc. Electrical connections all tight, grounds tight and clean, no vacuum lines cracked, loose or off that sort of thing. Not a Camry, but I remember I was doing some simple tune up work on a Mini once. Got all done and the car would not start. Went back and checked everything and found that the cap was not clipped down all the way and had popped up and off! lol. A mate of mine came over so I could set his carbs with the exhaust gas machine. He put new plugs in it before we started. Bought a brand new set of Autolites (NGK or factory Champion preferred) as they were least expensive. Ran well, got it going in the right direction setting it. Thought we'd give it a run to see how it compared to what he was driving (extremely rich). Car started to bog, sputter and all sorts. Went back through everything we'd done and found that one of the Autolites had gone bad. Swapped in one of my NGK's and the car ran a treat. Plug did not look cracked or damaged, but it certainly was not firing right.
Anyway food for thought. Hope that helps a bit.

[DOHCammer]

Originally Posted by Camry1999

I fill up every time i go to the pump, I just simple divide the miles driven by the gallons i put in. As far as the plugs, that's what I said.

When doing mileage calculations, accuracy increases with larger fillups. If you fill up early, differences in when the pump shuts off can cause quite a big discrepency to your mpg numbers.

If your plugs were misfiring then you would be getting a check engine light, so I don't think thats your problem. It's a good idea to disconnect your battery while you're doing a tuneup. This resets your computer and lets it respond quickly to your changes. I would check for a vacuum leak at any of the connections on your air intake hose. These cars respond well to a good throttle body cleaning and I would recommend one if you already didn't do it. Disconnecting the negative cable is a must for that.

[Camry1999]

I usually wait until i get to about 1/4 tank left before I fill up.