I have a 2003 landrover discovery and it has about 65,000 miles on it and the check engine light came on and and is flashing, the car seems like it is misfiring. i got the codes checked and it said the mass air flow filter needed changed so i did that but its still running the same. What could this be?

There is no code that tells you the exact problem try finding out what cylinder is missfiring then check the plug and wire or coil

Maybe you should check your fuel tank and clean them

Hello trish...you must have a really fancy code scanner because i have never had one tell me that...lol
When you say "mass air flow filter" i assume you mean mass air flow sensor (MAF)? If your check engine light is "flashing" it's telling you there is a more serious problem to be dealt with and you should have it repaired now to prevent additional faults..and possibly costly repairs in the near future.
On your landrover the scanner should read "Manufactured Control Fuel and Air Metering" fault if it's a MAF sensor fault. This fault does NOT always mean the sensor is bad, in most cases the sensor is fine and is doing it's job by reporting to the computer a problem it has detected...
The MAF tells the computer how much air and the temp of the air that the engine is getting.
Then using those readings and the readings from your oxygen sensors and the gear your in, engine speed, engine temp, and the list goes on and on the computer gives the engine the correct amount of fuel for the load it's under.
There are ALOT of variables and if one or more is out of sync it screws everything up...it's like a domino effect..are you with me still?
...After you replaced the sensor...did you rescan the landrover and clear the codes...because if you didn't...the computer still has it stored and nothing has changed? let me know what you find on the next diagnostic scan...that blinking light is not good.
Good luck..i hope this helps ya...please take time to rate me a fixya...
PS: make sure the gas cap is secured properly.

Bring the car to an authorized service center and have the computer box calibrated electronically...