Major decrease in fuel efficiency

[bbgunberrill]

I used to get about 850 km to a tank of gas about two years ago on my 2007 vibe. Now I'm only getting 400 to a tank. I have not done any upgrades on the car. I scrubbed out the throttle body yesterday and it seems to help a tiny bit. But the fuel consumption is still too much. I'll be taking it to the mechanic this week to replace the vvt filter. Any other ideas on how to get my mpg back?

[JohnO]

Have you ever replace the thermostat? They generally last about 5 years before they will start to open too soon and not let the engine warm up properly. Fuel consumption will then increase. The engine should reach at least 190°F (88°C) within a couple of miles after a cold start. Use a scan tool to verify the temperature.

Another thing to check would be dragging brakes. Jack up each wheel and verify it spins freely.

[rloftus]

Have you checked the condition of your transmission fluid? My mileage increased significantly after a tune-up that included new fluid.

[bbgunberrill]

I have changed all of my fluids. Including the tranny fluid. The brakes were all cleaned and touched up. How easy is the thermostat to replace

[bbgunberrill]

This is a response to JohnO: I tried your suggestion about brake drag. I had to put a lot of muscle into it and it only spun a little more than 90 degrees. So I called a mechanic and he said he would replace the callipers. He quoted me $380. I'm still scouting around. But I'll post my results after it's fixed.

[lannvouivre]

I have changed all of my fluids. Including the tranny fluid. The brakes were all cleaned and touched up. How easy is the thermostat to replace

Not SO bad, but not really fun. For easiest access to the thermostat housing, you have to remove the alternator and intake manifold. I read you only have to take off the alternator, but when I did it, the intake manifold was still in the way. The thermostat housing on these cars is low on the block near the pulley side of the engine.

[JohnO]

I replaced my thermostat without removing the intake or alternator. It is a little tight but not too bad. Only trick is that the new gasket looks like an o-ring but is slotted and actually installed over the edge of the new thermostat before it is put in place.

[bbgunberrill]

So I took the car in and had the breaks serviced. Now I get about 50 km more per tank. I'm glad I did this