Well, it looks like you have quite a list.
P0172- Fuel trim upper limit
P1008- Throttle system Warning- Signal low
P1017- ECM internal failure
P1027- Throttle unit internal faliure
P1620- Is an ECM (computer) problem, dash problem or wiring in between the two
Any one of these could explain the surging idle. Look for any vacum leaks, cracked or broken hoses. This one you may want to find a good Volvo shop, it looks like the throttle control may be bad, but it could have hurt the ECM given the internal ECM code.
Tuesday, February 2nd, 2010 AT 8:13 AM