I have a 4.2 that will quit running when I push the clutch in while slowing for a light or turning (I'm just coasting with the clutch in) It has 120k miles on it. It will start right back up (it may turn over a bit longer, but barely noticeable) There are no Trouble codes. I read the FAQs for this forum and one of the questions is related to the IAC but is for a 4.6 V8, would this apply to the 4.2? Could this be a dirty MAF? I checked for codes using my AE

 

if it is otherwise running ok, I'd look for a vacuum leak, check hoses.
the intake manifold runner control is an issue on the 4.2 also
search for IMRC problems here and just google it.