I have a 98 ram 1500 5.9L. when idling either when i first start it or while driving, it begins to idle real low and rough then sounds like it's sucking air then smells like it's flooding (every once in a while it will stall). I have to step on the gas to get it to quit doing it. Now, that being said, the truck has been a problem since I got it. The catalytic converter was clogged and is now hollowed out. The fuel pump went and has been replaced. Both the engine and transmission have been replaced. And the injectors have all been replaced multiple times in the passed few years. The IAC was replaced. Last summer, the entire motor was taken out, cleaned, replaced what needed replacing and put back together but no change. Please help. I have stumped multiple mechanics

 

Is the gas smell from the exhaust or under the hood? If exhaust, then the truck is running rich likely due to bad o2 sensors if they haven't been replaced in a while. Have you fixed the plenum issue? That is the reason the cat became clogged, it also has a bad effect on o2 sensors which in turn can make the truck run rich and cause idle issues.

The sucking sound is also not helping out your idle. Check the vacuum lines going to the intake for integrity and make sure none came off. Make sure you also have the gasket in place that goes between the throttle body and air hat.

 

the gas smell is coming from under the hood. the o2 sensors have been replaced a few times. I did just read through the plenum forum and believe that will be the next thing i do.

 

The plenum was taken out and cleaned and gaskets replaced

 

Running rich, or, a gas leak...... What's fuel pressure look like?