MAJOR loss of power HELP

[autumn61887]

Ok I feel like I am at a dead end, I have replaced just about everything in my car and it still has a major loss of power. I cannot gain speed uphill, pass people on a level surface, it basically seems like I am dragging a house behind me. I started with the spark plugs and found oil so i replaced the valve cover gaskets, then the rpm gauge stopped working and the car would not start on time so I put the car on a diagnostic. The diagnostic pulled codes for 2 o2 sensors, evap control system and a crankshaft position sensor code. I replaced all of the listed codes and the car still has major loss of power and the car still would not start on time so i put it back on a diagnostic. The diagnostic then pulled a code for the throttle position sensor and still crankshaft position sensor. So I took the car to the dealer to make sure it was the tps and why i was still getting the crank code before i spent $230 on the tps. They said that both camshaft sensors and the crankshaft(although new) were out and that the tps was fine. So now I have replaced the front cam sensor and the crank sensor and the car still does not have any power what so ever, wont start on time and the rpm gauge still does not work. I guess my main question is would the cam sensor closest to the firewall cause all of these problems or am I overlooking something.please help
Modified by autumn61887 at 10:08 PM 7/17/2009

[jltibbs]

Welcome to NICO!

IMHO, I would look to the cat.

[autumn61887]

Without knocking a hole in the cat is there a another way to check it?

[NutriaforBreakfast]

Please check the Mass Airflow Sensor first