Hi all,this is my first time here so be kind. I have the 2.4 GDI Chariot 1996 with similar problems, idle is rough slow of mark and doesnt change gear when in auto until revs get to 4k or above runs in tiptronic great, took it to a garage and he cleared engine light fault by just disconnecting battery for 15 seconds then it ran perfectly for 5 mins then back to original fault. After that he said code fault said it was the EVT ( electrinic throtle valve motor ,part of throttle body)very high price for new one he said Mitsi dealer had 7 in stock which is rare so must be common faulty item. I have since cleaned throttle body with brake disk cleaner again disconnecting battery for 15 seconds and it ran great for 5 mins arrggg. what i dont understand is if when battery is disconnected it runs great how can this be a electrical or machanical fault. any suggestions my unhappy GDI brothers. ps changed oil and filter ran an engine flush first used 10W-30 with an oil addative for tappet noise but now its even noisier what am i doing wrong, guy at shop said fully synth would be to thin for my high K's 140k.

thx for any help