I have a 1999 dodge durango v8 magnum 5.9 liter that im currently having RPM issues with. At first on my home from work i was at a stop light and the rpm started dropping and it died. So i started it back up and went on my way no problem. Now a few weeks later, on my way home it started doing the same thing but it didnt die just would drop in rpm and would chug when ever i stopped at a light, and when i would press on the gas and shift gears it would drop in rpm after it would gain speed. So finally i took the matter into my own hands and thought maybe a tune up would do since there was no check engine light on... but it didnt. I found out its burnt out our the wires cut. So i went and got it diagnosed with a machine at advanced auto and they said it was my O2 sensor. So i bought the 2 that are for my vehicle and went home to put them in and seen that one of the O2 sensors on my vehicle were rubbing against the drive shaft and was rubbing the rubber off the wires. So i thought okay theres the problem and changed it. Later on i took it for a drive and it was driving perfect in tell it warmed up and the rpm started dropping after i would gain speed and make it seem like i was applying the brake and again when i would stop it would try to stall and drop very low in rpm. To the point were you couldnt even hear the engine running so i took it back up to advanced auto to have it read again and its saying the same thing o2 sensor. Now i feel like im running out of options. Can anyone give me any advice?? I checked the catalytic converter for cracks our dings and it looks fine and sounds fine when its not chugging. Plus i took off my TPS and it looked clean as a whistle. Checked the air filter it basically looks brand new. fuel pump isnt making any weird noises comes on when i turn the car over.

 

I'd clean the battery terminals really well and clean the IAC on the throttle body as well. Those are the usual culprits for idle issue.

 

the fact that it only does this when its warmed up to me says that is is a sensor problem, since you already replaced the o2 sensors i would start checking the wires for them to make sure there arent any shorts in the wires. also what brand sensors did you get? i know there are a couple of brands that dont seem to work well in these trucks i cant remember which ones off the top of my head.


(unfortunately this isnt going to be easy to figure out).

 

They brands of the sensors are denso and NTK. Also will check the wires going to the sensors.

 

You should also check spark plugs and fuel injectors.

 

Sounds like what happened with my 98 ram when the catalytic converter started to melt inside.