Ford: 2000 ford tauru, ford taurus lx, ford taurus

Question
1....i have a 2000 ford taurus lx with 246,000 kms. the engine and transmission are in mint condition. it runs like a dream. i was getting 430 kms per tank of gas. but EXACTLY ever since the thermostat was changed, a hose to the firewall was changed, and the heater core was backflushed because the heat wasn't working well, and still isnt, the gas mileage has dropped down to 300-350 kms a tank.  there is no gas leak, and i dont know when the last time it had a tune up since i bought it in jan 07 with 238 kms. my driving habits are exactly the same. the air filter is new when i bought the car in 07. the pcv is ok, as noted by an oil changer garage, if that helps you. i actually only had 32f/32r psi in my tires before this problem arose.  now i put 40/f40r psi and the gas mileage is worse!!

2...and speaking of the heater in my car. i did a backflush, changed thermostat and a hose, but it still takes about 1 hour of driving in very cold weather for the rad needle to even move slightly, and the interior is very cold.  on days above freezing point, the rad needle moves normally.

3...lastly, can you confirm if ford stopped making the LX in 2004 (with the transmission shifter on the steering column)? why does ford make them on the steering column and on the console? which is more reliable?

any help would be appreciated

sk


Answer
we have been changing the o2 sensors in a lot of vehicle and it has increase  gas mileage on all the vehicles. what you need to do as far as the heater core is you have to flush the core buy itself.they both are reliable just the one on the column gives you more floor space