Sometimes it drives fine and sometimes the engine will start stalling?

There are a couple of thoughts on this one.

Flexplates were a problem that causes this, but I would lean towards a bad cam sensor. If you can scope it you may be able to verify it. The wiring to the cam sensor runs pretty close to the belt, look for chaffed wires first.

Hello, have you tried swapping relays? Maybe the ac relay is the same as the fuel pump relay, count the terminals, check the text on the relays, if their the same, swap, just for testing purposes. If the relays act the same, I don't think it is the relay. Check the relay control circuits, usually 85 and 86 terminals. 85 goes hot when you turn on the key. 86 terminal is ground, during the initial prime, the computer will ground that circuit for a couple seconds, after that, no ground without rpm signal.

Did you check for codes?

All indicate to a short circuit
DTC P0107: MAP SENSOR VOLTAGE TOO LOW
NOTE:For component location.

Manifold Absolute Pressure (MAP) sensor circuit is monitored with engine speed at 600-3500 RPM, Throttle Position (TP) sensor voltage less than 1.2 volts and battery voltage greater than 10.4 volts. DTC will set if Powertrain Control Module (PCM) senses MAP sensor voltage is less than 0.0392 volt for 1.7 seconds.
Possible Causes
MAP Sensor Voltage Below 0.04 Volt
(F855) 5-Volt Supply Circuit Shorted To Ground
(F855) 5-Volt Supply Circuit Open
MAP Sensor Internal Failure
(K1) MAP Sensor Signal Circuit Shorted To Ground
(K1) MAP Sensor Signal Circuit Shorted To (K900) Sensor Ground Circuit
PCM

DTC P0108: MAP SENSOR VOLTAGE TOO HIGH
Monitored & Set Conditions
Manifold Absolute Pressure (MAP) sensor circuit is monitored with engine speed at 600-3500 RPM, Throttle Position (TP) sensor voltage less than 1.2 volts for greater that 1.7 seconds and battery voltage greater than 10.4 volts. DTC will set when MAP sensor voltage is greater than 4.96 volts.
Possible Causes
MAP Sensor Voltage Above 4.6 Volts
(K1) MAP Sensor Signal Circuit Shorted To (F855) 5-Volt Supply Circuit
(K1) MAP Sensor Signal Circuit Shorted To Battery Voltage
(K1) MAP Sensor Signal Circuit Open
(K900) Sensor Ground Circuit Open
MAP Sensor Internal Failure
PCM

DTC P0118: ECT SENSOR VOLTAGE TOO HIGH
Monitored & Set Conditions
Engine Coolant Temperature (ECT) sensor circuit is monitored with ignition on and battery voltage greater than 10.4 volts. DTC will set if ECT sensor voltage at the Powertrain Control Module (PCM) is greater than 4.96 volts for greater than 2.6 seconds.
Possible Causes
ECT Sensor Voltage Above 4.6 Volts
ECT Sensor Internal Failure
(K2) ECT Sensor Signal Circuit Shorted To Battery Voltage
(K2) ECT Sensor Signal Circuit Open
(K900) Sensor Ground Circuit Open
PCM

P0205: INJECTOR #5 CONTROL CIRCUIT

DTC P1478: BATTERY TEMP SENSOR VOLTS OUT OF LIMIT
Monitored & Set Conditions
Battery temp is monitored with ignition on. DTC will set if the battery temperature sensor, internal to the PCM, goes above 4.9 volts or below 0.1 volt for more than 3.2 seconds.

Have to check wiring system and harness 1st use an OHM meter and check wiring back to the PCM if all checked OK suspect bad PCM

Hi:
on what you said, I would continue looking for another vacuum leak. Also, even though the check engine light isn't on, I would have the computer scanned at a nationally recognized parts store. THey will do it for free and there may be a stored code in the computer.

Let me know what you find.

Joe

Welcome to the forum. When the problem occurs, have a helper crank the engine, while you check for spark at the plugs. If you have spark everywhere, use a gage and check fuel pressure. You have to do testing, when the problem is ongoing.

Also, have the trouble codes checked. Some of the national brand autostores used to check codes for free. You can call and ask.

It sounds like the moisture is causing ignition issues. My first guess is the plug wires. What to do is this. At night, start the engine, open the hood, and mist water on the ignition wires, distributor cap. In the dark you will be able to see any arcing. If you find it, replace the part.

Let me know what you find.