i have a 89 2.8 rs. when i start the car in the mornings, i have to tap the accelerator for about 30 sec. the reason is that the car will seemingly cut off or will cut of in cold days or from sitting for some hours. the rpms will drop down to 0 if i dont tap the accelarator. when it does warm up it will not cut off. you can also hear the muffuler sound like a putt putt sound. when its in park it skips on the idle. the IAC,Fuel inject and presure regulator are new. could it be a bad fuel pump? please help me.