Hi all,

Yesterday evening I was driving my 1998 Volvo V70 (193,000 mi) on the highway through a national forest at 55mph. The service light flashed on briefly, then about 10 miles later the car began to do something I've never experienced before: even though I had my foot steady on the accelerator, the car's speed would slow to about 45, then suddenly speed up to 60 or 65. When the acceleration happened, the change in speed was so sudden that the car seemed to "jerk" ahead, almost out of control. None of the warning lights were on (besides the Check Engine light, which has been on as long as I've had the car) and the temperature gauge looked fine.

I managed to make it a few more miles into a small town. Even at lower speeds in town (25-35), the problem continued. The car died when I had to stop at a stop sign, but I got it to start again, pulled into a parking lot, and turned off the car. I tried to start the car again, and it started fine, sounded normal, but died after about 15 seconds. Someone suggested I check the oil, and I found that it was indeed quite low. I added two quarts of oil, let the car sit about 5 minutes, then started it and had the same result. Someone suggested I disconnect the negative battery terminal for 30 seconds. I did that, started the car and had the same result.

I am currently working on a research project in a small town in a remote rural area about 200 miles away from home. My car was towed back to the place I am staying here, where none of the few local shops are open on weekends. I'm planning to have it towed to a local mechanic on Monday. I wanted to see if anyone on the forum might be able to help me with these questions I'm facing:
(1) What are the right words to use to describe this problem to the mechanic?
(2) What might be causing the problem?
(3) Is this something that I can entrust to a local shop, or should I think about having the car towed (about 200 mi) to the Volvo specialist in my hometown?

The car was checked by the Volvo shop in my hometown about a month ago and came out with a clean bill of health. The oil & lube was done at this time. I checked moments ago and do not see signs of an oil leak under the car. As I mentioned earlier, the Check Engine light has been on as long as I've had the car (I got it with about 150,000mi) but people have told me this is common for Volvos and not something to worry about. It had been running fine. I had just fueled up about 15 mi before this problem occurred and had a full tank of gas.

I'm a newbie on this forum. Apologies if this topic has already been well-covered - I don't even know the right words to search to find an answer. Any help you could give would be much appreciated. Thank you!

Becky

 

After browsing the forum, it seems like my situation is similar to others who have experienced fuel starving, and perhaps problem with fuel relay, fuel filter, or fuel pump. I'll update with results from mechanic early next week.

 

Sounds like you might be right. I would say fuel pump relay.

 

The mechanic said that the diagnostic indicates a problem with the mass air flow sensor.

 

Very possible as well.

 

Thanks, tech, for your responses.

The mass air flow sensor was replaced, and this appears to have fixed the problem. The only remaining mystery is that since the MAF was replaced, when I first start the car the service light is on and stays on until I get above 45 mph. It turns off after that and doesn't come back on again until the next time I start the car. However, the car seems to drive fine.

 

That is an oil change reminder light. A special tool is needed to reset it on your car.

 

My wife recently had a problem where the car stalled and when started was blowing black smoke (mixture was too rich). The OBDII code was a PO243. Turns out it was the Mass Air Flow sensor (MAF). This is easy to replace. Even after it was replaced it took the tech about 1/2 hour of running it. The Service Manager suggested running it so the car computer could adjust to the new MAF. So far it seems to have fixed the problem. Also, check all of the vacuum hoses to make sure there are no leaks.