2000 nissan sentra?

56000 miles on this car, heres the problem,when l first start in AM and put in gear l can't pull out of garage, l must turn off engine,restart,put in gear,then it runs like a champ,took it to nissan dealer,big mistake, they replaced the fuel and air mixer,right behind air filter, $800 ,now when l start engine when cold l can pull away great,fast,now after driving a mile are two,turn engine off and let set for 10 minutes,start it up can barely pull away,shut engine off, resart and away l go normal, this car is driving me crazy,l don't want to take back to dealer, they don't know diddly,all they do is play take off put on and charg you and say try!