# Dodge Ram 1500 stalling issue



## Doc Schoepp (Dec 4, 2012)

The vehicle:
2001 Dodge Ram 1500 Laramie 4X4
5.9L V8 Magnum (all factory, no modifications)
150,8XX miles (transmission just rebuilt about 100 miles ago)

The issue:
Recently purchased this vehicle from a third party with no known issues. After about 24 hours of driving it stalled out on me a few times at slow speeds or at idle. Took it to pep boys where they did a full tune up on wiring, cap and rotor along with fuel system clean out. There was a bank 1 sensor 1 O2 sensor high voltage error code that they cleared as well. Worked for a day then same issue. Took it back and found out the torque converter was barely hanging on and most the rest of the transmission was about dead as well (bad solenoid, ect.) Rebuilt it and replaced the sensor because it showed a lot of corrosion and again worked great for a day then started stalling again. Had the oil changed and filter replaced but it was a free deal for Veterans Day so not sure how deep they went with the change. Still has issues when it is at slow speeds or idling. I watch as the oil pressure drops down to about 40-50, and RPMs start falling to 500, then 300 then the engine shuts off and everything goes out. Have had this happen siting at a red light, low speed turns and when coming down a steep grade tapping the breaks. Tapping the gas or switching gears will bring the oil pressure and RPMs back up with no issue. No engine banging or knocking but there is a high pitch screech which I was told was from one of the pulleys along the serpentine belt, possibly AC or tensioner. Working on replacing that once I get an idea on what is going on with the rest of the issues.

So my question is this, am I looking at sludging in the oil or a blown plenum gasket? I have done some research and seen both as a possible reason. O2 sensor still reads high voltage and if I clear it, it will come back on when the oil pressure/RPMs start to drop. I plan on replacing the PCV valve as well in hopes the $2 part fixes the issue where the $3,000 worth of work didn't. Hopefully someone has an idea because me and the mechanics at pep boys are out of ideas (unless I pay for a more detailed engine diagnostic that is).


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## octaneman (May 13, 2009)

Hi Doc Schoepp


Low oil pressure means you have a problem with the oil pump or the oil pressure switch is giving off false readings to the computer. Some models have a safety feature within the engine that when low oil pressure is detected the computer will shut down the engine to prevent serious damage. There is also the issue of the O2 sensor on bank 1 being contaminated by carbon deposits running through it. First, hook up an oil pressure tester to the engine and verify that its giving out the correct pressure. If that turns out to be OK, test the vehicles emission control systems for excessive blow-by gasses that the PCV valve, solenoids, hoses, are not leaking vacuum. 


post back your findings.


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## Doc Schoepp (Dec 4, 2012)

Ok, will start with that. Also noticed that the colder the truck is the better it runs. In the morning when it is very cold out I don't notice any oil pressure changes at all and it runs fine, longer it runs or the later in the day it is the more it wants to lose pressure and stall. Will let you know what happens when I get the tools


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## TeaMan (Nov 10, 2012)

I'm not sure that you have oil pressure problems yet. When your engine RPM go down so will the oil pressure. I'd look into why it won't keep the idle speed up.


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## Doc Schoepp (Dec 4, 2012)

Was not able to get the tools yet but the reason I am inclined to think oil is that the oil pressure drops before the RPMs do and that is the only time I ever have issues is related to the pressure. Hopefully the shop will be open tomorrow and I can grab a code reader and check the oil pressure


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## Doc Schoepp (Dec 4, 2012)

Ok, so their oil diagnostic equipment was broken when I went in but was able to pull the codes. There are three now:
P0455: Evaporative Emission Control System Leak Detected (no purge flow or large leak)
P0132: O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor1)
P0135: Oxygen O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)

I had the wiring checked when they replaced the cap and rotor and they said they checked the whole harness and replaced a few wires as well but cleared the electrical system once they were done. Replacing the PCV valve once everything cools down some. They should have the diagnostic equipment working by tomorrow. Any other thoughts in the mean time or what else I should check once I go in now that there are more codes thrown?


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## octaneman (May 13, 2009)

The emission system is where you should begin your diagnostics.Vacuum leaks are very common on emission control systems, inspecting cracked or broken vacuum lines should be the first order of business. If you got a scan tool available run the diagnostics on all the EVAP, EGR valve, actuators throughout the whole system, the problem could be localized to one area. 

The O2 sensor on bank 1 sensor 1 is malfunctioning which is giving false readings to the computer to trim out the air/fuel ratio. Heated O2 sensors are pricey remove the sensor and visually inspect it, if the O2 sensor on bank 1 is carbonized you will have to replace it.


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## Doc Schoepp (Dec 4, 2012)

I had just replaced the sensor about a week ago when they rebuilt the transmission. They said the old one showed corrosion and since I already had the new sensor they threw it in since it was easy to access with transmission out. Sometime over the weekend I will try to get the EVAP system checked. Helps to have a free DIY auto center with tools. Just wondering what is causing the new one to trip. Would a vacuum issue trip a brand new sensor like that or could the other two be bad causing that one to trip?


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## octaneman (May 13, 2009)

Doc Schoepp said:


> Would a vacuum issue trip a brand new sensor like that or could the other two be bad causing that one to trip?




Yes it would; O2 sensors primary role is to _detect_ oxygen in the exhaust gases in the manifold and pipes which in theory should be none because its a sealed system. A vacuum leak destabalizes the air/fuel ratio, any variation outside its parameters will trip the computer's fault code.


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## Doc Schoepp (Dec 4, 2012)

Thanks for the help so far. Replaced the PCV valve which was loose fitting and about black with carbon. Cleared the code and about five minutes later the CEL came back on but this time just the P0132 high voltage. Will dig deeper into the EVAP system tomorrow when it is light out.


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## Troy_Jollimore (Dec 31, 2007)

One thing to try would be to take a propane torch and lightly crack open the gas flow. With the engine idling, run the tip around your intake piping and around where your intake goes into the motor. If the engine races, you've found a leak.


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## Doc Schoepp (Dec 4, 2012)

Ok, was a pretty busy week so not much time to play with the engine like I wanted to. Switched out the air filter as well since it could really use it. While I was doing this I found the gasket off the back of the air intake had blown out. Got that replaced and seems to be running better. I did find that the clips in the back of the filter housing were broken and cause the back to pop open a bit. Zip ties fixed that for now. Hoping the gasket was the issue and this is all done. Nothing else visibly damaged or leaking that I can tell. Going to try a homemade smoker later today if I have the time.

Would that gasket be part of the issue or was that an incidental finding? Still learning the workings of the different systems in the engine and what connects to what.


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## octaneman (May 13, 2009)

Doc Schoepp said:


> Ok, was a pretty busy week so not much time to play with the engine like I wanted to. Switched out the air filter as well since it could really use it. While I was doing this I found the gasket off the back of the air intake had blown out. Got that replaced and seems to be running better. I did find that the clips in the back of the filter housing were broken and cause the back to pop open a bit. Zip ties fixed that for now. Hoping the gasket was the issue and this is all done. Nothing else visibly damaged or leaking that I can tell. Going to try a homemade smoker later today if I have the time.
> 
> Would that gasket be part of the issue or was that an incidental finding? Still learning the workings of the different systems in the engine and what connects to what.



Would the gasket be part of the issue ? Absolutely. Your engine had multiple vacuum leaks that exacerbated the problem. Vacuum hoses, gaskets, exhaust leaks, all have a direct impact on how the engine runs. Emission systems have the highest rate of failure and are the chief culprits when engines run poorly. Over time vacuum hoses crack and break off because of engine heat, clips become corroded and loose their clamping ability to maintain a tight seal around the vacuum ports on the intake manifold and the air filter housing.


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## Doc Schoepp (Dec 4, 2012)

Ok, so after some time off during the holidays here is where I am at now. Replaced the IAC as the original was covered in carbon and would not actually clean off. Pulled the throttle body and cleaned that out, pretty bad carbon build up there. Fixed the throttle gasket as that was also blown but didn't come up on the smoke test. All this and it still idles at maybe 600 and still dips when breaking and idling trying to stall. Had a friend with an oem reader do a diagnostic check and everything was good except the b1/s1 O2 sensor malfunction. Every time I reset the CEL it comes back on within 20 min of driving and the RPMs dip into the 200-300 range. Thinking of resmoking the air intake again to double check. 

Only thing I have not messed with is the squeaking pulley and replacing the serpentine belt. Not sure if this would make a difference as the belt is starting to show some wear on the sides and the pulley chirps/squeaks once warmed up. Can't find anything else with the air intake so could it be fuel line issues? Electrical was already cleared at the shop during the tune up but the b1/s1 o2 high voltage will not go away.


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## Doc Schoepp (Dec 4, 2012)

Also was told to look into either a bad/clogged fuel filter or throttle position sensor. Any thoughts as to which? I know the fuel filter is in the fuel pump which requires the entire fuel tank to be dropped where as the TPS is right there on the throttle body and an easy replacement.

Also forgot to mention that even though the O2 sensor is reading high voltage, which to my understanding is too rich, when is stalls it is acting as if it ran out of gas. Lights dim and the engine cuts. Also once or twice I have had the issue of going up a hill and suddenly losing momentum where it did not matter how much I hit the gas the engine would not run any faster until it hit the top. First time it knocked once and went back to normal the second time did not here any detonation. This happened on about 3/4 to full tank both times Not sure if this helps at all.


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## TeaMan (Nov 10, 2012)

There should be an inline gas filter, not the one in the tank. It's a good possibility as it affects your fuel pressure.


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## Doc Schoepp (Dec 4, 2012)

TeaMan said:


> There should be an inline gas filter, not the one in the tank. It's a good possibility as it affects your fuel pressure.


Just checked the Chelton manual and did some googling and my understanding is that my year dodge does not have an inline fuel filter. I physically checked around the engine and undercarriage as well but did not see anything. Not sure if I am missing it but to my understanding it would look like a canister with a hose leading in and a hose leading out, correct?


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## TeaMan (Nov 10, 2012)

Right, and it's gotta have one somewhere. Maybe it's a spin on canister like the oil filter. It would be in the engine compartment.

EDIT: it may not be a rubber hose hook up. It can be metal lines and require a special tool to decouple it.


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## wolfen1086 (Oct 4, 2007)

I know this is probably a stupid question but how full is the oil level?
Your rpm should be somewhere around the 500-700 range with a V8, and a squeaky pulley ain't dropping the rpm's unless its seized, and the belt is being pulled across it. An bad vacuum line could mess up the rpm, along with some sensors too, Your fuel filter is in the tank on the end of the fuel pump just like My Jeep is, here's a hint: Yes you can put one in line BUT you gotta have HIGH PRESSURE lines, preferably using steel or Brass flare fittings, not rubber hose (never use rubber hose there)
I'm not sure abut the O2 sensor high voltage though, you might very well end up with a simply O2 sensor replacement all the way up to a automotive electrician looking at it on that one. But if its like my Jeep in any way its either the sensor or the electric solenoid that gives it its power


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## Doc Schoepp (Dec 4, 2012)

The oil was just changed maybe a month ago and is still sitting right near full and still looks decent. Pulley must have fixed itself in all the snow because it no longer squeaks and nothing is seized. 

Reason I brought up the low RPMs is because when it idles at 700 it runs fine. As soon as it drops to 500 idling is where I see the dips down to 200-300 and the stalling occurs. It basically acts as if I ran out if gas but then starts right back up if I put it in neutral and turn the key. 

Already replaced the sensor once so what kind of chances are there that I got a bad one? Going to pull it and take a look probably when I drop the gas tank. Also, is it possible to replace just the fuel filter without the whole pump? I have read that some vehicles need the whole unit replaced while others you and do just the filter. Not sure which mine falls into. I am debating on replacing the TPS but not sure since I would think that would be causing issues the whole time and not at random


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## octaneman (May 13, 2009)

Doc, 


Clear out the IAC motor with decarbonizer. Since your engine has been running rich for quite a while, carbon deposits have most certainly built up within the orifice of the IAC. After cleaning the IAC fire up the engine and let it reach operating temperature, throttle up the engine to 1500 rpm and spray de-carb through the intake, flush it out as best you can then go for a road test and see if there is an improvement.


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## wolfen1086 (Oct 4, 2007)

TPS could possibly be a issue with rpm. personally I'd do that first just cause I hate dropping tanks, but there's no way for me to tell you if the filter can be changed without actually looking at the pump itself, but most mechanics will tell you to replace the pump since your going that far into it, that's up to you though, not totally necessary if the pump works right.
the odds or getting a bad sensor right out of eth box are real slim although it has happened to me before once or twice, but I work on cars about 3 days a week too so........
700 is a good rpm for idle for an automatic if its dropping dorm lower when it goes to 500 it may not be a fuel pump issue. odes it drop to 500 all the time or just after being driven?


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## TeaMan (Nov 10, 2012)

The TPS can raise hell with idle speed and you can check it with a multi-meter to see if it's within the range.

You'll need the specs for it though.


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## wolfen1086 (Oct 4, 2007)

I think a Haynes manual might have the specs but I do know for a fact the dealer will. When I had a Dodge Truck (95 d150) it was in section 6 under the emissions stuff and not the easiest to find but it was there


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