Another possibility is a a bad injector. Bad pattern or low opening and/or closing pressure. You can pull the injectors and check the patterns. Typically if the opening or closing pressures are off the pattern will be bad too. Techron is a good try but if it doesn't work and you have one or more bad injectors, you will have to have them cleaned. Should have the whole set done even if only 1 injector appears bad. David teitelbaum --- In dmcnews@xxxxxxxxxxxxxxx, "daveswingle2" <swingle_dmc@...> wrote: > > Rich. Bad O2 sensor or frequency valve. Or something in that ECU circuit. > > --- In dmcnews@xxxxxxxxxxxxxxx, Soma576@ wrote: > > > > > > Hey all, > > > > The last couple of years my D has had a slightly rough hot idle. It's at around 900 rpm most of the time when hot, and it kind of wavers down to about 500, then surges to 1000, then back to 900 or so.... A couple years ago it was very smooth so I know what it can sound like. The car starts easy cold, after a couple of cranks hot, and has plenty of power. It's not missing. > > > > I added a bottle of Techron to a pretty low fuel tank to shock clean the injectors in case they got dirty. I know everything in the tank is good, and I have checked all the obvious stuff like vacuum lines. > > > > Anyway I can smell the exhaust at hot idle and it smells like extinguished matches - a little like sulfur. > > > > Does that sound like a rich or lean condition? > > > > Andy > > > > > > > > > > > > > > [Non-text portions of this message have been removed] > > > ------------------------------------ To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnewsYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: dmcnews-digest@xxxxxxxxxxxxxxx dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/