My 98 Accord V6 coupe is burning way too much gas and I can't figure out why. My mileage is about 2/3 of what it should be.
I had the exhaust flex pipe replaced b/c of a leak..but that didn't fix the problem.
When the car is in park and I rev the engine the rpms come down to about 1000 and stay there for a second, along with vibration that sounds like it's coming from somewhere along the exhaust system, before dropping back down to about 750rpms(idle).
The only thing I've done to the car is replace the stock air filter with a Green performance filter, everything is pretty much stock and the car is well maintained.
Any help is appreciated.

 

You live in Toronto which is cold. I'm just going to say that the denser cold air requires more fuel to combust at the correct ratio. My gas mileage always dives to about 2/3 of what it is in the summer and I live in Minnesota. As for the 1k rpm thing it's probably just coming off of "fast idle". As for the rattle, the exhaust pipe is probably rattling againt a heat shield.

 

yeah, it's normal for the idle to stop at 1000 rpm as it comes down from a rev and then stabalizes at 750. any other symptoms?

how's the transmission?

 

The transmission is good, I'm on my second, the dreaded 6th gen. curse. I ran my scan tool on it last night at the P0420 code came up, so I'm thinking oxygen sensors and a catalytic, funny didn't get the CEL. The code for a small evap leak also came up.

Thanks for the feedback so far!

 

the CEL won't always turn on just because there's a code... Our cars try to make sure it's a real problem, and will store the code until it's hit a few more times (I've heard 2-5 times depending on the code) to solidify that you DO indeed need to check it out.

but if you see a code, there's a good chance that it will act up again unless you're just lucky