check engine, code 66, mafs

here it goes.....my check engine light comes on after about 10-15 minutes of driving(when the engine is warm)

i have horrible gas mileage....about 150-200 miles to the tank, and it gets progressively worse

took it to the mechanic....tested it for codes....code 66 came up which is the MAFS......the sensor was replaced, and codes are suppossedly clear.....but i still have the check engine light coming on, i don't think the gas mileage had improved either

any suggestions?????????? PLEASE HELP! thanks

you should check for codes again. if the light is on again there is more codes.good luck.

If code 66 is still present,you could have bought a faulty maf. If the maf is good, you may have a computer problem

ahhhh more codes, any suggestions?

well because my mechanic wouldn't recheck codes, i bought my own. the maf code didn't come up, thankfully. however i did get some others.
code 14: would this be crankshaft sensor?

code 67: neutral gear switch, clutch switch ( i do have a 5spd )
what does this mean, what should i check?

code 41: exhaust gas oxygen(ego) sensor reads "lean"
i guess one of my o2 sensors is bad, even though
i just replaced at least one of them. is there anyway
to check them?

thanks guys for the help, if i figure it out i'll let ya know

Codes

Ihave a book for the eec-iv codes #67 clutch switch circuit failed make sure to do this test with the air conditioner circuit off if still present then you should replace the neutral drive switch.It basically lets the engine rev up a little so the car does not stall when u engage the clutch.Code 41 if you have replaced them recently then check the plug wires,the fuel pressure.the dis,the spark plugs and look for vaccum leaks.I would use brake cleaner and spray around all hoses if the car revs then u have a leak in the area near where u sprayed.There is too much unburned air getting to the oxygen sensors so they r giving you a problem code. Hope this helps!