My cousins boyfriends Elantra is stumbling and dying at idle, if I hold the throttle plate open it'll stay alive put has a miss or flutter. I just replaced the axles and did an oil change, at the same time I sprayed the MAF with some MAF cleaner and allowed it to dry before I started the car. The only other thing I did was degrease the engine and spray it down at the You-Wash Spray-n-Wash place. The code it's throwing is P0121 which the way I read the book is a TPS sensor. I checked the connection and it's not wet, I also checked to see if the spark plugs are wet and they were dry too. Has anyone had this problem and did a new TPS fix it? I just had this kid drop $250 on axles and I hate to have him spend another $60 if it's not gonna fix the problem. Thanks in advance.

 

Changed the TPS, no change. Did notice a lot of steam coming out of the tail pipe, but theres no water in the oil and I don't believe the car has ever overheated so I don't think the block is cracked. The only thing I can think is that either the crack in the exhaust flex is causing it to stumble or the Seafoam I put in the gas tank is having an adverse effect. Any thoughts?