Volvo suddenly slowing down for no reason



Hello! I have taken my car to numerous mechanics over a number of years, but nothing can be found, and the problem even seems to be happening more frequently as of late. Basically, my car will suddenly start slowing down, and won’t respond to the gas pedal. I have to turn the car off and on and again and usually it will snap out of it. This slowing down happens several times a day.


How many miles does the car have? Being an 89, might I assume its a lot? And you say this problem has slowly been getting worse over a number of YEARS?
The car isn’t completely dying, right? It’s basically just idling even though you’re hitting the gas?

The good news is, now that the problem is getting worse, your mechanic is more likely to be able to find the problem. Personally, without knowing more details, I’m inclined to suspect your Throttle Position Sensor. With years and miles, the TPS can develop staticy readings or dead spots that confuse the car as to how much fuel to give. With the car warmed up, a mechanic should be able to test it with a voltmeter.


Without knowing if the problem is fuel or spark related, and making a wild guess, I’d say it’s a failing fuel pump and/or pump relay. Over time, if the former is failing it can knock out the latter.


One cause, in an 89 anything, used to be a contaminated oxygen sensor. Fuel injected cars have them and they used to last about 50,000 miles on some cars.

Shutting it off and restarting could mean something else, like the engine control computer or a related part (which one?) could be scrap metal.