It can happen at any stage of a drive: went i first start out, 5 minutes into city driving, after 30 minutes on an expressway. When going slow, very slow acceleration with a throaty sound, going fast and the car starts to slow down and if i press her down, it actually goes slower. Here is the strange part; if i put it in neutral and turn off the ignition and then restart the car, it goes back to running well.