my wifes car has 140,000 miles on it and its paid for so i have to try to fix it myself before taking it elsewhere - tried to trade it before all this happened for a civic and they hurt my feelings so we have decided to drive it until the wheels fall off but im afraid that may be soon if i cant fix it - i have read other topics on this problem but have not solved it yet - OK it started out by check engine light coming on - this was the 171 code so i bought a O2 sensor - naturally it was for the one just before the catalytic converter and not the one on the exhaust manifold - so i got the wrong one - anyhow i didnt put it on yet - then the transmission wouldnt go into od and i knew it was low - after this i drained all the transmission fluid twice and refilled with the correct t-4 fluid - reset the light and it did fine for about 20 miles - then light came back on and it wouldnt go into 3 or maybe OD - it was taching about 3000 on interstate - anyhow i tried cleaning the maf or map sensor just behind the air cleaner with the spray cleaner and that did work for about another 20 miles then light came back on - dont know where to go from here - the transmission shifts and sounds acts fine until light comes on and you get out on the road -the fluid was dark but no pieces or hunks on the plug or in the fluid - i have not changed the O2 sensor yet so that may be the problem and causing the transmission not to shift - i do believe however that the transmission was low before all this started because it does have a small leak but i never checked it until the car wouldnt pull itself in the driveway - then i checked it and it was low - i got the right fluid put in it and it did fine then - anyhow this is where im at now - anyone have any suggestions before i take it to a real mechanic ??? thank you for any help here