My 2004 v70 was purchased certified used and has a stalling problem. What I noticed initially is the car would stall out when I came to a stop on extremely warm days where the AC ran hard, and restart easily, but idle very rough and stumble as if it starved for gas. Eventually it would settle out. It stored no codes. At this point the car was due for plugs and I replaced them (50k miles). It also stalled when I turned right through water over the road during or after a strong storm.

Under normal driving I found the idle would drop below 500 rpm when I came to a stop then bounce until it settled in the normal range. The car would be sluggish from a complete stop. It stored no codes. After several visits to the dealer for service they replaced the fuel pressure regulator. It made no difference. They reprogrammed the transmission, and this made no difference.

I've taken the car to the dealer at least five times....it never stores a code and they never find anything wrong.

About a week ago the car was at 99,970 miles (30 miles left on the warranty) and I drove through standing water and it died. It restarted and I drove it right to the dealer. They said they found a code but were not sure of the cause and would need the car for at least a week. They gave me a loaner to drive.

Today they called and said the car was fixed. The engine control unit was going into failure and was replaced. I asked if the replacement part was new or reconditioned and they told me it was new and had a 12 mo. 12,000 mile warranty. I am picking up the car tomorrow.
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I'm stuck on Volvo and Volvo's stuck on me....