Problem Problems Alfa Romeo GT 1.9 jtd 150 hp


I also bought an Alfa GT from 2005, 1.9 jtd 150 hp, full variant. I like the car and I would like to keep it. I have one problem and question though, the car does not pull at low revs, more precisely below 2500 revs, it has to to step it well from the 1st gear so that it also pulls into the 2nd and the 3rd gear. I specify that I have had more than 10 cars (mostly diesel) and I know how a car behaves, especially at 150 hp. what do you think it could be ?