Hello all,

I bought a used 1989 Camry v6 2.5L back in January '07. I purchased it with 150,000 miles on it.

Since I've had it, it has gotten bad gas mileage. A few weeks ago, I found out that it had a blown/cracked head or something so I decided to have the engine replaced with one imported from Japan.
So, all in all here is a general run down of all the parts replaced.

Engine, Fuel Filter, Spark Plugs and Cables, Cap & Rotar, Radiator (was leaking), TPS, MAF, etc. even with the newer engine that I'm told only has 35-40K miles on it, I still get bad gas mileage. I'm only getting about 200-250 miles per tank of gas, if I'm lucky.

I know that I can't and won't exspect to get "great mileage" out of it compared to what newer cars get today, but I would think that I should be getting at least 300 miles a tank?
From a full tank, I can only drive about 35-45 miles before it tells me that I am down to 3/4's of a tank.

So, any ideas what might be causing this? I'm thinking that maybe it could be the O2 Sensors although I don't have a Check Engine light on but I've heard that they could still be going bad but are not bad enough yet to activate the engine light.

The pipe running from the exhaust to the muffler has a somewhat small hole in the pipe right before it connectes to the muffler.

I really need some help with this! Tired of spending money at the mechanics just to have basic tests ran with no answers yet.