Now for fixing the problems i would first start with the code 11,
When the crank sensor fails, the engine will die but no code is set. Code 11 will only set if the computer has never seen a pulse from the crankshaft rotation sensor. If the engine has been running in the past, this code will not be set because the computer remembers that the sensor was working. To check for this fault, the computer memory must be erased.
When you have a no-start condition, disconnect the battery for about 15 seconds. Reconnect and crank the engine for 7 seconds. Now pull the codes again. If you get a code 11, it means that the crank Hall Effects sensor or its associated wiring is defective. To determine whether the sensor is bad or the wiring is bad:
- locate the wiring harness connector closest to the distributor or crankshaft position sensor.
- With the ignition switch in the off position, disconnect the three-wire connector.
- Now turn the ignition switch back on and measure the voltage on the three wires at the computer end of the wiring harness.
- At least one of the wires should have between 7 and 10 volts. This is the power supply wire for the Hall Effects.
- One of the other two wires should have a voltage that is a little lower than the power supply wire. When the engine is cranked, this signal alternates between 0 and 7-10 volts as the Hall blades rotate. The alternation may be too fast for many voltmeters, but the indicated voltage will be less than the supply voltage.
- The third wire, the one without the voltage, should have continuity to ground.
- Verify this with a voltmeter. Remember that the ground wire, although it will be continuous with ground, will have some resistance in it. Expect the resistance to be somewhere between 0 ohm and few hundred ohms. If the resistance reads infinity, this wire is open and must be repaired.
- If the wiring harness checks out good, then replace the Hall Effects sensor.
Now for the code 13 No change in MAP sensor, This could be caused by the code 11 sending the wrong info. So i would fix the code 11 then reset the computer and see it comes back.
Code 21 Oxygen sensor problem the o2 sensors are working it is selling you the exhaust is not right caused by either the code 11 or 13.
Code 42 I would check the battery cables and ground wires. If they check out ok the fuel pump may be going out
The fuel level unit is the fuel sending unit it is what runs your fuel gage