sounds like you need to reset your ecu, not tune it. its possible you may need some type of afr controller, but you should have one already. make sure your battery terminals are tight, and has good ground contact. is your ses light on? what codes do you have? does it let you drive over 3000 rpm? there should be a reason your experiencing problems starting, so you should pull those codes.
to fix your idle, do the 3 relearns in order. you can do each one multiple times if you are unsure you did it correctly. the exact procedure and prerequisites are in the fsm. you should do these:
1.accel pedal released relearn
2.throttle plate closed relearn
3.idle air volume relearn
here's a reference:
http://www.b15u.com/sentra-specific...learn-throttle-body-relearn-idle-relearn.html
to fix your idle, do the 3 relearns in order. you can do each one multiple times if you are unsure you did it correctly. the exact procedure and prerequisites are in the fsm. you should do these:
1.accel pedal released relearn
2.throttle plate closed relearn
3.idle air volume relearn
here's a reference:
http://www.b15u.com/sentra-specific...learn-throttle-body-relearn-idle-relearn.html
