Hey guys, first post here but I've been "lurking" for quite some time. Quick question though.

When replacing the sensors do I need to replace both o2 sensors or just the one closest to the engine? If you could read below on my problem.


2001 Dodge Ram 1500 5.2L V8, starts and runs/drives without much issue but I have a nagging problem that's making me a bit mad. When the truck starts on a cold start it idles and runs fine for about 5 minutes, then once the engine is warm, I'm assuming it goes into closed loop, it wants to die/choke itself out. Once I gas it, the RPMs will surge to around 3k then drop back to normal and continue a normal idle. At this point it will either run just fine with no more issues or try to choke out a couple more times.

This also happens sometimes when driving, you can feel the truck start to die out. I have to let off the gas then re-gas it to make the truck "catch" itself. Sorry, I don't know a better word to describe it.

I'll be checking the fuel pressure tomorrow but for now do you think it could possibly be a faulty o2 or possibly bad MAP sensor? I had a code thrown a few days ago regarding the o2 sensor but went away and hasn't popped back up anymore. Thanks for the help guys

 

If the 02 sensor are original with over 70,000 miles on them, then there both bad and need to be replaced (don`t use bosch 02 sensors). The crank shaft position sensor can also go bad and cause the problems your having, but not throw a code. The map sensor can also go bad, but it doesn`t seem to be a common problem on our trucks.


I would replace both 02 sensors and the crank position sensor if there original with lots of miles on them.

 

You could try simply disconnecting the front O2 sensor, (the one before the cat) and see if it runs any better. That will tell you if the sensor is the problem.

May not hurt to test the throttle position sensor as well....

 

I got irritated with trying to figure out which sensor is causing which problem, so I replaced a bunch of them all at the same time. CPS, MAP, TPS, O2 sensor, plugs/wires...also addressed some wires and a half-missing fuel injector the local squirrels had chewed up.

Currently on my 2nd crankshaft position sensor...that ones a PITA. Check my post history for a write-up on how to change it.

 

I've replaced the crank sensor already. Extreme pain in the ***.

I've also replaced the TPS as well. To include plugs and wires, Idle air, cleaned throttle body, new ignition coil and a few other things not coming to mind right now.

I'll replace the o2 sensors when they come in. I've got them on order.

 

Disconnect the front O2 sensor, and drive the truck. See if the problem goes away.