S70 Surges, periodic hard starts, and periodic ETS light
 

From what I have read this is symptomatic of a bad ETM, but I want to be sure. Everything I have read suggest that with a failing ETM there will be power losses at cruise speed. My car does not have this, but rather the opposite. It surges at speed and also on deceleration. When dropping to idle coming to a stop it will surge as if you pushed the throttle.

It also has periodic hard starts and the ETS light comes off and on. The cruise works most of the time, but sometimes stops working. It will reset after you cycle the key. The ETS light also does not seem to affect if the cruise works or not.

In fact the ETS light does not seem to correspond with any of the symptoms. I had coded pulled and there were mulitple codes for IAC....which the car does not have. There was also a code for the cruise control brake switch, purge valve, and O2 sensors.

I am not a mechanic by trade, but I have done a lot of work on later model cars, so I do understand the technical side of all of this.

I am leaning toward getting the contactless ETM first, but I don't want to jump the gun if there could be something else causing the surge. I have read that MAP sensor can be an issue, but I have no codes directly pointing to MAP. I do understand that this can be a hidden issue with no codes.

The closest volvo dealer is 100 miles away so a sweep test is not a real easy thing to get done.

Any help is appreciated.

Fuel filter
 

Surge at idle , worse when cold ? difficulty starting ? Ets light comes on sometimes shortly after cold starts ? Or even when doing highway speeds ? This is a clear sign of fuel filter blockage.


It's easy to replace. The hose has clips that you push towards the filter to loosen. When replacing bracket, remove it and reset the angle of the bolts thread, so the bolt can go into the thread.

Fuel filter
 

Surge at idle , worse when cold ? difficulty starting ? Ets light comes on sometimes shortly after cold starts ? Or even when doing highway speeds ? This is a clear sign of fuel filter blockage.


It's easy to replace. The hose has clips that you push towards the filter to loosen. When replacing bracket, remove it and reset the angle of the bolts thread, so the bolt can go into the thread.