Have a 2002 GMC 2500 Duramax. Just put all new injectors in it. Drove 40 miles out of town and it started losing power. If you let off the accelerator it will gain a bit of power and when you try and accelerate again it does a nosedive and you can only get up to 20 mph. I was told it was the prime pump. Anyone have any answers? All help is greatly appreciated