The car will idle hard until I get the revs up and then it will stay even ... but driving the car it hesitates in 2nd real bad and will hesitate in 4th.. real bad..

Suggestions? All I did was replace the MAF and get everything put together

 

is your CEL on? flashing? what the hell car do you even have?

 

did you put the maf on backwards? i accidentally did this when putting an intake in my 1.8t. it ran how you describe. freaked me the f out haha

 

Why??

Take it apart and do it again, correctly.