Cougar

Oh, the horror and shame! I can't look upon it. This is why a factory wiring manual is worth its weight in gold. Purchase a new resistor pack from the dealer. You might have to replace that damaged relay socket along with the relay also.

The OP stated they heard a click but it is hard to say how fast they are moving the switch to the START position and may be hearing things turning on while it moves through the RUN position. I assume the click isn't loud and coming from the starter solenoid since the starter has been replaced and it should be in good shape.

Since the starter has been replaced the most logical suspect is the inhibit safety switch. It ia a common issue on older Soobs. The contacts get dirty and that prevents power to get to the starter solenoid.

The service items just keep repeating after 120k miles. Along with the timing belt, the tensioner and others things in that area should be changed out also.

See if the engine will fire up using some starter fluid sprayed into the intake. You didn't mention anything about spark so if that hasn't been checked take a spare plug with you so you can plug it into one of the wires to check that out.

As others have mentioned the timing belt is the most critical thing you need to know about. Hopefully the Carfax report will give you some clues about that or a shop you can refer to for info about the service. There coud be a number of things causing the CEL to turn on. A common issue is the knock sensor goes bad. Hopefully it isn't related to the CAT operation.The outside temperature reading problem might be due to a bad connection. I think there is a connector in front of the radiator at the bottom of it that ties to the sensor. For the rear defroster problem see if you are getting voltage to the connection point of the heater grid. If you don't have there then suspect broken wires in the flexable tube running into the rear hatch door from the roof.

Power to the blower passes through the fuse, then to the relay, to the motor, to the resistor pack, and then to the switch to ground. See if you have power getting to the motor with the switch on. If you don't have power there then you most likely have a bad relay.

The trouble might be due to a faulty ignition relay. I think it switches power to those areas you mentioned. It also might be the ignition switch is having a problem. Check the voltage getting to the dash fuses while the ignition switch is ON. See if they have voltage to them. I don't have access to my service data right now but we'll get this figured out.

Glad you found the trouble. If it happens again I would suspect the inhibit switch first. They are a common issue for that problem along with the starter solenoid contacts wearing out. You will hear a load click from the solenoid when they go bad and you try to start the engine.

This is a common problem with the inhibit switch.

Since you have eliminated the starter as possible trouble it does appear that there is just enough resistance in the ignition wire to the starter solenoid wire that it keeps the solenoid from pulling all the way in and close the solenoid contacts so the starter motor can turn on. I would check the inhibit switch to see if that is causing the voltage drop. Another possibility for the trouble could be with the main battery wire to the starter. Check the voltage on the wire at the end going to the starter and make sure that voltage is above 10.8 volts while trying to start the engine. If it is below that then make sure the battery end is above that voltage also. If the voltage at the starter end is low then the cable has a problem internally and it needs to be replaced.

I could see how low charging voltage could cause all of the code issues the OP stated were happening.

I forgot about the differences between the 2.2 and 2.5 liter engines like Rooster2 mentioned. Your engine has major work required to fix it. That being the case it might be time to think about moving on and getting what you can for this car. If the rest of the car is in real good shape it might be worth investing in a used replacement engine and other ware items but you are going to have to carefully weigh the differences between the two. One thing about totally rebuilding your engine is it should go a long time without any problems. Some might recommend going to the 2.2 liter engine which was preferred over the 2.5 due to less problems.

I assume there was no compression because the timing belt has slipped. There might be a problem with the belt tensioner. I also assume that the valves weren't damaged. If that is the case then replacing the timing belt and other things may be worth the time and small investment for new parts. You need to decide that. If there is valve damage then that would really hurt. I would invest in a newer car myself but that is just me.

When I posted on this issue earlier I didn't really consider the charging system being the cause of this trouble Fairtax4me. Now, after thinking about this again I actually feel there is a better chance of that being the real cause of the trouble rather than a power connection problem to the injectors. I think you nailed it.

No special tester is needed to do the testing. I'm not sure what the specs are for a nonturbo engine but I would guess you should see between 150lbs to 180lbs of pressure on a good cylinder. Hopefully all the readings are within 10lbs. of each other.

Checking the error codes is a good easy thing to do. I suggest you check the compression first before removing the belt cover. It might save you some time if the results show no trouble with the compression.

The voltage going to the injectors should be about the same as the battery voltage. If the battery voltage is around 13 volts and the injector voltage is at 11.8 volts this might indicate there is a power connection problem to the injectors. You could try running a temporary power jumper lead to the injectors to see if that helps. I also recommend you clean the engine grounds to see if that helps with the misfires though that might be happening because of the low injector voltage. There could be a valve problem with #4 cylinder. If spark to the plug is ok and the injector doesn't have a problem then check the compression of that cylinder and compare it to the others.

Having the engine die while driving isn't a good thing. You appear to have fuel and spark so I have to wonder if the valve timing has slipped since you stated the timing belt appears to be intact. The results of a compression test will tell you the story about that. I think that car has a non-interference engine and if that is what has really happened that would save your rear end.

I suggest you first clean the battery post connections, even if they look okay. Along with that check the fusible links for a loose connection. They are located inside the small black box mounted on the coolant reservoir. If you still have trouble after doing those things you then should check to make sure the fuses are getting power through the ignition switch by using a test light probe on the dash fuses. Place the probe tip in the slits on top of the fuses to check for power. If the power to the fuses is okay while the trouble is occurring then you need to check the inhibit switch on the transmission

Why don't you use a FM transmitter for your MP3 player to work with the radio?

From your comments about the sensor output voltage it seems that you aren't seeing any change of voltage while at idle or high engine revs. This can mean either the sensor is bad, but you have already swapped it out with another one, or there is a wiring problem to the sensor. The reference voltage wire is possibly bridged to the sensor output wire. Remove the connector to the sensor and then check the voltage on the sensor output lead. If you still have 4.5 volts on it then the wires are connected together at some point or there is a problem inside the ECU.

Going by what Fairtax4me states, it appears you may have a bad sensor. The info he stated was that the voltage output should be low during idle and high voltage, near 5 volts, while the engine is revving pretty high. Your info shows the opposite. High voltage while at idle or high vacuum.

I would have to say it appear to be a gasket failure to me.

Unfortunately I think you have a head gasket problem. The flickering lights may mean the alternator has a regulator problem. It might be happening while getting over heated and something is breaking down.