Why rpm jumps during accelaretion between 25mph to 60mph
crwdns2934249:0crwdne2934249:0:
Hello friends
I have explorer 2009
During idle the rpm is constant
During accelaretion from 0mph to 25mph the engine is smooth
During acceleration from 25mph to 60mph, when I'm in 1500-1400 rpm, it jumps to 1800rpm with rrrrr noise and go down back to 1500rpm.
Its happened several times until I reach 60mph, and then the car drives smoothly.
If I will accelarete with higher rpm, 2000rpm or more, the rpm jumping doesn't accure
What is the cause?
Please help
Thanks