Warning! Long post follows!!

Strange problem. My wife called me at work and said her 940GL couldn't leave the grocery store parking lot. It wouldn't build up any speed, but it wouldn't die either. After about 15 minutes, she called back to say it started running properly again and was able to drive home without further incident.

That evening, I checked it out and could find nothing wrong. I installed a set of plugs and wires and drove it several miles. It ran great. Then a couple of weeks later, it did it again. This time, she was just a few blocks from home and she limped it home. It never did start running properly that time. When I got home, I drove it and it was perfect! No problems! Since I didn't doubt her experiences, I decided to take it to our local repair shop. We were able to leave it two days. They could find absolutely nothing wrong. It drove perfectly for them. Good fuel pressure. No codes. They had worked on our Volvo a couple of times in the past, including installing a new fuel filter and pump a couple of years ago. They've always been very good to us, and have always stood behind their work.

Today, I got to experience the problem myself. It started stumbling, missing a bit, and wouldn't drive over 10 mph. Idle was extremely erratic. My wife said she would kill the engine and it would always restart. It did the same for me, but never recovered. A few times on the drive home, I would pull over, kill then restart the engine. If I gunned and revved it very high, it sounded fine. But it would return to the very erratic idle and would not drive properly.

This Volvo has been our family since new. It has about 250,000 miles, and my wife loves it. I'm hoping I can get it to the shop while it is acting up, so they can see firsthand what it's doing. But chances are, it'll run perfectly while they have it!

When this has happened, it's been very cold out. And we're keeping the tank full. Airbox looks good, and clean. Any ideas? Could it be a fuel injector problem?

As always, thank you very much for your time and suggestions!! We always appreciate your help!

Steve