2000 Ram 2500 4x4 5.9 gas about 170,000 miles. My problem: When cold truck starts fine but has high idle 1400rpm running smooth though. After 10min. or so it starts boggin and chuggin then stalls. When I try to restart it it will just crank like its not getting spark or fuel. Let it set for 10min. or so and it will start right up but only run 1-2min at this time then the boggin and chuggin again. The only code was 1391 bank 1 sen 2. I replaced the O2 sen. at the rear of the cat. NO help with that. Tested the TPS got 1.1v at idle and 3.88v at wot. the book says the volts should rise to slightly under 4.5v at wot. I'm not sure if 3.88 qualifies as slightly under 4.5 any suggestions on that would help. Also attempted to test the MAP sen. It has the volts it needs going to the sen. At this time I don't have a vaccum pump to test the output volts. My question is do you think I'm going in the right direction or am I way off base. It has not had a tune-up since before last winter. Could cap and rotor be the problem? Any help much apprecieated.

Thanks Dave

 

I'd check my fuel pressure at the port on the fuel rail next.

 

Unplug the pre cat O2 sensor, and drive it for a bit. See if that doesn't make any difference.

 

like heyyou said drive around for a little while with the pre flow o2 pulled out. the post flow o2 doesnt have much affect on how your engine runs its mostly the pre flow. and a word of advice if it turns out ur pre flow is bad, get a NGK brand not a bosch. they tend not to work with 2 gen trucks.

 

Fuel pressure at the rail is 49psi when its running. When it suddenly cuts out pressure at rail drops rapidly.( drops after engine stalls ) Question is should it drop from 49psi to 0 within 10 - 20 sec. Again truck runs smooth then sudden stall. Each time I turn the ignition off then back on I hear the fuel pump kick in for a few seconds. I'm lost.

 

Can the coil be cutting in and out when the truck gets warm? Because after it stalls and I crank it it seems like it's not getting spark or gas. And I just put 5gal gas in it just in case the fuel gage was bad. Still no luck. Thanks Guys

 

Sounds like more than one problem. The fuel pressure should not drop like that. So the regulator is bad and the fuel pump needs replace. I'd replace it first and see what happens. If it continues to stall like that when warmed up, I suspect a failing crank sensor.

 

Replaced the fuel pump. Thought everything was okay. Drove the truck about 10 miles after replacing no problems. Drove the truck the second day , started out with no problems (10-15 miles) as I turn into my driveway it stalls. Starts giving me same problems I had before. I'll try the crank sensor. Can a clogged cat. cause this problem?

 

Clogged cat would give other symptoms as well.

How long does it usually take before you can restart the truck? If it fires right back up, I don't think it will be the crank sensor. Have you tried swapping the ASD relay, with the Horn relay??

 

I'm only assuming, but by the way post # 6 reads. It doesn't fire right back up.