I have a 99 Sonoma, 2.2l, SFI, DIS, auto. It has a starting issue that I can't figure out. Sometimes it will start before the engine makes a complete turn. Other times it will crank about 6 revolutions before it starts and then it is rough for about 10 seconds before it idles properly. In 10 starts it is about evenly split between good and rough starts. It does not matter whether it's a cold or hot start. I have about 45lbs. fuel pressure and a 3 lb. drop after it starts. The regulator hose is dry. The filter is new. Cycling the key makes no difference. Your thoughts please.