My engine stalls while driving?

I had a similar problem with my 93. It turned out to be a faulty PCM relay. I would be driving along and the engine would die. After a minute, it would restart and go for a while. It is located in the power distribution box under the hood. Check with your owners manual for the location.

I found this guide that can help us fix it as well

https://www.2carpros.com/articles/engine-stalls

Please run down this guide and report back.

What you are describing is indicative of an electrical component getting hot and failing. Often in the ignition system like a control module or coil.

Next time you get home after a drive and have some time to mess with it, try to restart it. If it wont start, pull a spark plug and verify that you have a good spark.

Do you have the 2004 computer, wiring, and sensors in the Ranger? Is it the correct computer for the type of transmission you have? Is this a "new" symptom, or has it been this way since installation?

Next, I suggest that you put some diagnostics on the engine. This has the sound of a bad mass air flow sensor. Also, you should never clean the throttle body. Cleaning it will cause idle problems and hesitations.

You should definitely have more pressure in the fuel system. The system is designed to have a constant pressure across the injectors. With vacuum, the pressure will be lower, without vacuum, it should be higher. The reason for the constant pressure is for the PCM to calculate the proper duty cycle for the injectors to dispense the correct amout of fuel - without adding more variables.

Probably the reason you had to prime the system is that the PCM is apparently not controlling the fuel pump relay. The PCM is programmed to run the pump for a few seconds on power-up and turn it off until it "sees" an ignition signal to turn it back on.

The trouble codes you are getting are most likely the result of having a "hybrid" setup that the system was not programmed for. I would suggest that you start by getting a '04 PCM from a stick shift. This will eliminate the transmission codes. The EGR code could be coming from a problem in the wiring.

Keep in mind that the entire SYSTEM was designed and programmed for a different vehicle with a different type of transmission. Your task now is to satisfy the PCM. When the PCM is not happy, it goes into a default programming mode that is essentially a cold engine program. Performance and driveability suffer ein this mode. Simply changing parts is not likely to solve the problem(s).

Well, why not start with the easier stuff first.
First thing you need to find is a reasonably priced DIY junkyard. We have them in my neck of the woods, not sure about where you are. Around here, a computer only runs about $10 to 20 if you pull it yourself. Any Explorer or Ranger computer from a 4.0 with stick shift should be OK.

A really good starting point would be to get a Haynes manual for the car that the engine came from. Look at the wiring diagram. You can get a used power distribution box and wire the thing yourself without too much complication. The important things are the PCM power relay and the fuel pump relay. There is a very good reason that the PCM controls the fuel pump - SAFETY! If you were to develop a fuel leak or be involved in a collision that compromised your fuel lines, the PCM will shut off the fuel. Without the relay and the inertia switch, the fuel keeps coming. If you try to restart at that point, without a safety system, you could potentially have the entire contents of the fuel tank leaking all over. One spark, and you have a "towering inferno"!

The loaded question is whether it is worth it. Only you can decide that. You have the potential for a good usable truck that can serve you for many years - assuming the rest of the vehicle is in good shape. Rust and general condition are the main points to consider.

BTW, fuel pressure is very important. The system is designed to operate on a predetermined fuel strategy that is programmed into the PCM. That is why there is a pressure regulator and a high volume/high pressure pump in the original. If you don't have the right pressure, nothing else you do will matter.

I need you to check something. On the 94, there is a relay called the Electronic Engine Control (EEC). I have experienced people with the same vehicle saying they drive, it runs fine, they stop and it won't restart. If the relay is bad, it will shut down the fuel pump and spark to the engine. When it doesn't start, switch the EEC with another relay in the box that has the same part number. See if that fixes the problem. If it does, replace the relay.

It sounds like a crank sensor. Have you actually checked fuel pump pressure? I realize it is new, but there could be an issue with the regulator. Has the check engine light come on?

Based on your description, when going up a hill, there is more demand for fuel. Therefore, I would start by checking fuel pump pressure.

Here are directions for checking.

https://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

You will need a fuel pressure gauge. Most parts stores will lend or rent them. Check that and let me know what you find. Also, let me know if the fuel filter has been replaced.

Joe

If the O2 sensor or MAF was bad, it would have set the check engine light. As far as the catalytic converter, that could be a problem. When the engine is running and at normal temp, look at the converter. Many times when they are plugged, they get red hot. If it is red, replace it.