hELLO
This type of problem is either a defective crank sensor or Ignition control module or a defective electric fuel pump. To run a test of the systems electronic control unit go to this link for instructions, the fault codes are there as well. To confirm that you may have a loss of fuel pressure and a possible electric fuel pump problem do this, get a can of spray starting fluid from the auto parts store or hardware store,the next time the engine won't start (I'm assuming you mean the engine cranks over but will not fire up, correct?) spray the starting fluid into the air intake hose of the engine, if the engine fires up you need a new fuel pump, the fuel pump is located inside the fuel tank, the fuel tank must be removed from the car to replace the pump.
TO REPLACE PUMP FOLLOW THE INSTRUCTIONS BELOW
Jack the
vehicle high enough to slide the tank out from under the vehicle. Support it with jack stands. Disconnect the fuel pump wiring harness connector at the fuel tank. Loosen the hose clamps on the filler hose where it attaches to the fuel tank. Loosen the hose clamps on the overflow hose, which is next to the filler hose. Remove the filler and overflow hoses from the fuel tank using a common screwdriver to pry them off.
Place the jack under the fuel tank and make sure it is centered. Remove the two bolts in the straps holding the tank up. Once the bolts are removed, pull the straps down and push them out of the way.
Begin to lower the tank until there is enough clearance on top of the tank to remove the fuel lines attached to the pump. The pump will be centered in the tank. The fuel lines can be removed by loosening the clamps with a common screwdriver and pulling them off. The third line--the vapor line connector--is made of plastic and is designed to come off by squeezing it with your fingers, which spreads it apart and allows it to be pulled off.
Lower the tank to the floor and slide it out from under the vehicle. The fuel pump is held in by one of two ways: it either has a round screw-on cap, which is easily unscrewed, or it has a flat ring with tangs on it. The ring has corresponding tangs on the tank. Place the screwdriver on the inside tang and tap it with the hammer (counterclockwise) to release it.
Lift the fuel pump from the tank. Note the direction it is pointing at the top where the fuel connectors are. Also note the position of the fuel sending unit float as it is extracted so the new pump can be installed the same way. Install the new pump the same way it came out. Install the new o-ring that came with it on the top of the tank under the cap. If you have a screw-on type, screw the cap on. If you have the ring, lay it flat and start it in the tangs by hand, then tap it clockwise with the screwdriver and hammer.
Lift the tank up enough (using the jack) to install the fuel lines. Plug in the fuel pump wiring connector. Lift the tank into its proper position all the way up and position the straps around the tank. Insert the bolts in the strap and tighten them.
Remove the jack and push the fuel filler line on, as well as the overflow line, and tighten the clamps. Remove the jack stands and let the vehicle down.
