I traded my 1988 Suzuki Samurai straight across for this 97 dodge ram 1500 5.9 Magnum. It is an automatic/4x4. When I first got it the guy told me it takes forever to start when it is cold. I am not a mechanic and hadn't had much experience in things mechanical. Long story short, it was the head gaskets. at first I thought it was just the plenum/intake manifold gaskets. It was taking forever to start and then it would blow lots of white smoke. So I did the plenum/intake gaskets. It was still blowing white smoke. So it had to be the Head gaskets. I then replaced the head gaskets and the manifold gaskets again.
Truck seemed to be running great! No more blowing white smoke and it would start right up no issues. Before fixing the head gaskets we had tried using the head gasket repair crap. Now we have been having issues with the truck just stopping out of no where on us. At first it wasnt critical. It would happen and we could restart the truck soon after. I replaced the Ignition coil and for a time that seemed to have fixed the issue.
Now the truck is critically down. It won't stay running longer that 15-20 minutes. Seems to die and not restart once the engine is somewhat warmed up! It doesnt even reach operating temp before the truck shuts off. The truck wont restart unless it sits for atleast an hour. I have been researching what it could be and have already poured a ton of money into the truck without any luck!
I have replaced the following items all in the hopes it would solve our issues.
Head Gaskets, Plenum/intake manifold gaskets, ABS wheel speed Sensor, Throttle Position Sensor, Crankshaft Sensor, Cam Sensor, Distributor cap/rotor, Spark plugs, Spark plug wires, recently an oil change and transmission fluid/filter change, ignition coil, all new fuses, new serpentine belt, vapor canister purge solenoid, coolant temperature sensor, fuel rails.
I was leaking some gas on the right fuel rail. I thought that might be part of the issue. I replaced both fuel rails with a whole setup I took off of another truck from a junk yard. I am no longer leaking gas but the problem is still here. The only code that I am getting is p0118 which has to do with the temp sensor that I already changed! The temp guage is working in the truck.
The truck will start right up if it has been sitting. It will stay running for about 10-15 minutes before dieing. Once the truck shuts off it will not start it will just crank and crank and crank. I start to get a smell of gas in the cab after it cranks over for a while. Also, when it is running, if I rev up the engine, the tachometer wont rev past 2000 RPM....I can put it in reverse and drive and drive back and forth for a bit until the engine decides it wants to shutoff. The only other sensors I can think of changing at this point are the o2 sensors and the MAP sensor. I did remove the o2 sensors and tried to start the truck and it didnt chanmge anything so I wiped them off and re-installed them. I also had and issue with the 4x4 light being stuck on. I unplugged the sensor for it and left it unplugged for a while and plugged it back in the light went off and stayed off. I am pretty positive it isnt stuck in 4WD. Please help me with this issue! It is driving me nuts and costing me a ton of money!!! Luckily, I have a take home company vehicle for work but we seriously need our personal vehicle working!!! Thank you for any and all of your input!

 

If those sensors aren't genuine Mopar ones that could be your problem. These trucks only like Mopar sensors in the critical areas. You need to see what you are losing when it won't start. Something is getting hot and failing

 

Also, your truck has two temp sensors, one for the gauge in the dash, and another the PCM uses to run the engine. The important one is cleverly concealed between the a/c compressor, and thermostat housing.

Need to find out what is missing when it won't start. Spark, fuel, injector pulse.

 

Well that would be unfortunate for me because none of them are genuine Mopar parts. Just the cheap ones from O'Reilly's auto parts.....that would seriously suck if I have just been wasting money ....

 

I will say this if they do work they won't work for long as they are known (crank) to go within a year. I never knew that until HeyYou said that. I didn't believe him (I'm stubborn ) and he was right. See what you lost when it won't start (fuel or spark)

 

all the parts that I listed have been replaced within the last 3 months without even driving the truck more than a few yards back and forth in my yard lol...I will have to look into it further on my next days off. This truck is making me wish I had a much older vehicle with no sensors....it's crazy how one stupid sensor causes the whole dang truck to be out of commission! What would be the best way to test what it is missing when it won't start so I can figure out if it is fuel or spark? Thank you for both of your input this far!

 

Grab yourself a can of starting fluid. Pull the filter housing off the throttle body, and squirt some in there. If it fires, and runs for a few seconds, you have a fuel problem. If it doesn't fire at all, you have a spark problem. If you can draft a second person, you can also pull the coil wire off the coil, hold it a little bit above the coil, and have someone else crank the motor. The spark should jump that gap, if you are getting one at all.

 

This is easier than my suggestion I was going to say!

 

awesome I will try this on my day off on Sunday and let you know how it goes. Thank you!

 

The parts stores use cheap sensors that technically work in your application. They don't communicate properly with the PCM though. I've had good results with Mopar or Standard Motor Products (SMP) sensors on our Dodge. SMP has a good line, a value line, and also make BWD. You need to get the regular line. They can be had at Rock Auto, AutoValue, Bumper to Bumper, and Amazon. There is a similar problem with ABS wheel bearings, I prefer SKF. Their sensors communicate properly with the vehicle.