I have a 1996 sunfire 2.2 with 120000 miles. Two weeks ago I got a problem with the crank position sensor and put a new one in. A couple days ago ithe engin started to lack power and smoke. Checked the spark plugs and they are black and unburned gas on them. The plugs and wires are new so the airfilter. Could someone give me tips on what the problem is. There is no engine light on so problem is hard to find.