Have a 2001 s60 that was just purchased. Has 171,000 miles on it. Problem that happening is car surges/jerks while in automatic mode mode of the transmission at 40 mph. I can put the car into manual mode and it goes away? Was told could possibly be a spark plug but I wanted to see if anyone else has had the same problem.

 

Is there a stored code?

 

 

It seems unlikely to me that a spark plug would be speed sensitive but they're cheap so swapping them out wouldn't hurt anything. I would be looking at the throttle body. Volvo calls it an ETM. They are prone to failure on your year of car. XeModex has a good product that addresses the parts that are prone to failure.

https://xemodex.com/us/product/elect...6001821-10-20/

That page also has some useful troubleshooting docs to help with the diagnosis.

Normally you'll get a code though. Are you using Vida or just an OBD2 scanner? An OBD2 scanner won't pick up any codes that deal with the system bus including an ETM error.

 

 

Some of the troubleshooting docs on the Xemodex site deal with problems after a swap. Personally I would be looking at the fuse and relay they mention and testing them as a first step followed by a thorough cleaning of the throttle body using an appropriate cleaner before dropping 500.00 on a rebuilt ETM.