It's all fixed, Turns out it was an EGR valve. Almost 600.00 total between the guess parts, and then when real parts it needed when the "dealer" diagnosis it right. This time I'm going to give the dealer the thumbs up. john PS. just want to thank all the people in this group who tried to help.
The EGR (exhaust gas recirculation) valve is an important emission device. It meters in exhaust gases into the intake to lower the peak combustion temps in the engine - this lowers oxides of nitrogen (NOx), which is a component of smog (along with hydrocarbons and ozone) and is formed under high temperature combustion. Most cars have used them since the 70's.
EGR valves are usually vacuum driven and on today's cars controlled by the engine manangement computer, with inputs from sensors. They meter in the exhaust during cruising. For the engine to run well, they must not let ANY exhaust in during cold running or idle. They can get stuck open by being worn or coked with carbon and then exhaust gets by them. Or ehty can be told to open whrn they should not - a bad sensor could casue this. An engine will idle poorly or stall if it lets exhause gases in during idle. If they are malfunctioning at other times, poor drivabilitry will result.
Not all late model engines have EGR valves. IN the case of VVTi and VVTLi engines for example, the same function provided by an EGR valve is accomplished by intake cam timing adjustment.
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