[chitowndad]

In general today's engines all work the same, they feed data to a computer and when one sensor is starting to go the car does silly things like you mentioned but the sensors are still within specs so they don't throw a check engine light. Google "car dies when stopped" and you'll see what I mean, everything from a bad vacuum hose to the Mass Air Flow sensor.

Find a good mechanic and describe your problem. He/She doesn't need to be a Porsche mechanic just one that understands how to troubleshoot.

My guess it that most likely it's one of the following:

MAF - dying when coming to a stop and idle "hunting" issues (up/down, up/down)
Coolant Temp Sensor - rough idle issues at either warm or cold
O2 sensor - bucking when running at a constant speed on the highway

and several more general symptoms that I can't think of right now but any good mechanic can educate you.

If it was my car, I'd first replace the ignition switch (DIY) then tap on the MAF when the engine is idling. If the idle changes, replace the MAF. Then search on this forum and then I'd post the WEB for someone that has software that can read what the computer is doing.

Keep us all posted

Good luck.

-Steve