I have a 1993 Mitsubishi Diamante DOHC with a auto tranny and lately it has been acting up first it would shift fine from first to second then from second to third its like it completely disengages and just increases rpms like in neutral until you let you foot if the gas and then it shifts it has also went into limp mode twice we had a spare ECU witch we swapped out the engine performance increased and it hasn't gone into limp mode but it still is having problems shifting from second to third. Is the torque converter bad or maybe the Trans axle Control Unit? also it shifts fine from third to Overdrive

 

could be a bad shift solinoid in the trans

 

EDIT now it seems to be popping in and out of limp mode and when not in limp mode it shifts funny with O/D on but shifts fine with o/d off besides second to third WTF?

 

are you getting any codes ???

 

no check engine light and i Also dont have a code reader

 

I have a 2000 Diamanté and it all of a sudden went into limp mode today!!! Not sure y yet??? Any help would be great!!! I've had the car for a month are so and it has damage on the front drivers fender... The running lights I had to wire because of the damage.. Nothing else has been wrong with the car until today!!! I'm letting any codes clear while I'm in town and will check it when we get home.. When I figure out what it is I will post it!!!!