Problems with 2010 Nissan Altima AIR BAGS

2010 nissan altima s (purchased new 12/7/09) and as part of the incentive to buy the vehicle, the dealership had after market leather installed and from there the problems have been non-stop. at this point, i believe the problem is electrical. i have taken my car nearly 10 times (one being today) in the past 15 months for service and was placed in loaner cars at least 4 times due to the problems. the passenger seat air bag not working and tire pressure light sporadically comes on both blinking and/or a constant. my entire seat was replaced and still the air bag light takes up to 5 minutes sometimes (it varies) to turn off indicating someone is in the seat. i have driven up to 4 miles with my passenger being unprotected. the dealership, today says this is normal. the tire pressure light has came off and on since the car was purchased with nothing found to be wrong each time, except once, they said i had a nail in my tire and they plugged it. i have never seen the repair work and looked very well... this past weekend, i vacuumed my entire car (meaning each door had been opened and shut) taking approx 15 minutes. when i got in the vehicle and tried to start it the shift was locked and the car would not start. all lights started blinking and then completely shut down. it would show "on" on the start button while not running. i was jump started and then instantly the tire pressure light blinked for one minute then stayed constant. the air bag sensor took even longer to work. of course, when i took it to the dealership today, nothing was wrong--battery was good--air bags are good; however, they did confirm low tire pressure in one tire... i truly believe it is an electrical problem and the company is not standing behind their product. i am beyond frustrated and truly dishearten by nissan and their lack of concern for their customers' safety and well being. *tr