Question about my friends auto tranny.....

[BlackBulletTSi]

My friends 95 Eclipse GS like when he floors it in second it goes to redline and then shifts to third but only for like a second and shift right into fourth.....it didn't do this before according to him. Now is this the ECU doing it or is there something else. He's driving me crazy and I just keep giving him some lame excuses and they've been working but now its buggin me cause I wanna know haha. Any help is greatly appreciated thanks!

[teh DIRT]

actually.its most likely the TCU (transmission control unit).

id say its the throttle position sensor.

Full throttle =shift at redline

Light Throttle= shift earlier

if the TPS sensor isnt reading correctly it could be telling the TCU to shift prematurely

[BlackBulletTSi]

ahhh I'm an idiot I ment TCU haha.......actually ok I lied I forgot about the TCU for a min I knew it had one but I'm an idiot haha. Alright so how can I go about testing the TPS?

[teh DIRT]

umm
well you could get a voltmeter and test its voltage outputs

mine rangers from 0-4 volts. 0 being at no throttle and 4 being at full throttle