misfire on cold starts

[RickHaleParker]

RickHaleParker, did your clogged resonator show up as high backpressure or did you have a rattle?

We could hear it, the same loud whistle one gets with a clogged catalytic converter. I open the exhaust system between the catalytic converter and the resonator it went away, that told me it was not the catalytic converter, did the same between the resonator and muffler it did not go away, that isolated it to the resonator. One could start from the back and work forward, might save the cost of a clamp.

If you have a rattle, get under the car with a stethoscope, listen to the catalytic converter, resonator and muffler as somebody shakes the exhaust system. The internals of catalytic converters, resonators and mufflers sometimes break up causing back pressure and a rattle.

[mhamiton]

I wanted to post back with an update. After several attempts at the local Volvo dealer resulted in them saying "we can't fix your car, good luck," it finally ended up at a competent dealer in Burlington, NC. Long story short, after 2 weeks (and a supposed "tech team" looking at the car) they diagnosed a bad fuel pump control module. That is on order and should be replaced this week.

[RickHaleParker]

The Burlington, NC dealership is saying it was taking too long for the fuel pressure to build up ... it fits the symptoms.