1998 Infiniti Q45 - TROUBLE Accelerating Past 40 MPH @@

I have an 1998 Infiniti Q45. Today, as I was getting off the highway onto an exit ramp my car started to jerk. I had sloweddown to 40 mph and everything was fine. But as soon as I hit the accelerator and went over 40mph, it started to jerk again and wouldn't accelerate past 40. If I kept a slow and steady pace on the pedal then I could ease past 40mph. I pulled into the grocery store parking lot and stopped at the stop sign before entering the lot. When I made a complete stop, my car just turned off completely. I turned it back on and it started, but I had to rev the engine and keep it going. I drove back to my house which was literally 4 tenths of a mile away and as soon as I pull into my subdivision I notice smoke coming from my hood. I stopped the car in my driveway and have left there. After lifting the hood I notice that something had exploded/burst in there and splattered all over the inside. It came from the front of the car. I couldn't make out the liquid, but it may have been oil. I had unscrewed the oil cap and there was smoke coming out of there. What is the problem?