Volvo: 98 S70 - stalling when in idle, engine thermostat, orange arrow

Question
QUESTION: Hi Ray,  My 98 S70 has started stalling when I'm in idle - it sometimes happens right when I start the car and other times only after I've been driving for 20 minutes, just before it stalls the RPM'S drop & the orange arrow lights up and then all the lights come on.  It usually takes about the time of a full green light to change for me to restart it.

I've taken it to the transmission specialist who found nothing wrong and to the Volvo dealer now 3 times - they have so far replaced the engine thermostat & sensor, changed the cable to the gas pedal, something with the vacume on the intake manifold (I'm now in Quebec - so my receipts are in French which aren't as clear)and cleaned the throttle link & the ventilation of the casing and replaced the grid.  

I've also noticed (which I haven't mentioned to the volvo dealer yet) that my key sometimes sticks in the ignition when I'm turning off the car and I have to turn the car on and put it in gear and then turn off again. Though not typically on the same trip as the stall..  I read somewhere on here -- that maybe that could be the cause (ie. ignition module?)?

Any advice is appreciated as my 4th Volvo appointment is tomorrow and I'm already out $1,200.... thank you!!!!
Jess

ANSWER: Jess,
What fault codes are posted? You may have a bad air mass meter. If the dealer will work with you have them install the Air mass and see if that helps. Does the engine begin to "miss" when it stalls as if there are some bad plugs cap rotor or wires? There should be misfire codes if that is the case.
For the ignition lock, make sure that the shifter is in park and the button is popped out. It may need an sdjustment on the cable from the ignition lock to the shifter. Some locks also have gone bad and needed replacement. I have seen some that the button sticks and needs some lub to free it up.

---------- FOLLOW-UP ----------

QUESTION: Thanks so much for your response, Ray -- they say it has an exhaust leak and I need to replace the exhaust manifold (another $1k....).  Does that sound right for the problem?  I'm not sure what you mean if the engine "miss's" - it's more like rpm's dropping and and the engine doesn't "catch" when I try and start it...  We realized it only stalls when I'm in a lot of stop & go/city traffic.

I'll try the button trick on the ignition lock.
Thanks again!!

Answer
Jess,
Can't say that an exhaust leak repair will take care of stalling, unless it is so bad that it has an affect on the MAF sensor. Have they driven this car in the way it takes to make it stall? Can you take a tech for a ride to show them your problem?
The price might be a bit high, but that could be the labor rate that drives up the price.