I have a ‘94 Ram 2500 with the 5.9 magnum. The engine is suddenly qutting. I’m always braking when it happens but most of the time when I brake, it still runs fine. It is dying suddenly as if I turned the key off - not spluttering or running rough. Then it won’t start again until several hour later. It will turn over and having deleted the muffler I can hear it firing a bit I think but it’s not near as loud as when it runs. Give a few hour and it will start and run just fine. The engine has been cold each time it’s done this. All the spark plugs, plug wires, distributer cap and coil rotor? were replaced last summer. About 2 weeks ago I had the master cylinder replaced. It’s been running fine until yesterday. I’ve gone over all the fuses and all the wiring except in the dash. There is no CEL on. Any ideas?

 

The power brake booster could be shot. When you hit the brake, the booster sucks excessive vacuum for the engine to operate. You could try plugging the brake booster vacuum line and try that to be sure, but your brakes will not operate as before of course. What bugs me is that it should fire right back up unless you have your foot on the brake. If that is not the problem at least you have eliminated that possibility. Another thing that will kill an engine under operation is a bad crank or cam sensor, that should get a check engine light.

 

I'd check the IAC, my 1500 was doing this before- especially when braking downhill. I cleaned the carb and replaced the IAC sensor. Problem solved.

 

 

 

500 is a bit low. Fully warmed, should be around 600 or so.

Need to find out what's missing when it won't start. That will point you in the direction you need to start looking.

 

Hmmm, I'd check it out just in case, mine was idling fine in park, but I cleaned out the IAC housing and replaced the IAC itself. Seemed to do the trick.
Have you tried testing the connection to the throttle position sensor (TPS)? As well as looking in the carb to see if anything is obstructing the plate?

 

 

LOL, I'm sorry- your right. Old habits don't die- I meant "throttle body".
Not 100% sure, I've never had to mess with mine, but i've heard some tales..
->unplug the tps harness
-> set your meter to 20 volts on the DC?
->turn ignition to on
-> attach red to battery, black to the prongs inside the tps harness
->They should read 12 volts, if not, you have a bad wire
I'm not positive about the voltage coming from the actual TPS itself.. Hmm
Have you looked inside the throttle body? WHats it look like?

 

TPS testing:
http://www.enduringautomotive.com/tps/