new truck, not a normal dodge person, but do love it so far, have a code 21, o2 sensor, how do I know if it is the pre cat or after cat, also, the truck will die sometimes sitting at an idle, seems like maybe it stumbles also will driving constant speed, any help, thanks in advance, Lee

 

just ordered 2 new sensors, be here in 2 days, still want to know about stalling

 

Does it also have a hard time starting maybe cranking a little longer than it should? Clean or replace your AIC

 

Mine would stall and miss every now and then on the highway and when I first started it. I replaced the rotor, cap and spark plug wires and it fixed the problem.

 

cleaned aic , no better, cap,wires and all look pretty new, gonna drive me crazy,any help

 

cleaned aic, no better

 

You might need a new IAC motor they are a commonly failed part and relatively inexpensive