I always considered myself one of the lucky few who didn't have any significant issues with the ETM on my 99 S80 T6. But because I had intermittent flat spots on acceleration, I decided to take it when when I received the software upgrade notice.

As soon as the upgrade was done though, I started noticing some issues. When I start the car cold (either in the mornings, or when leaving work), it starts as if it's out of fuel - it stubles for a few seconds in between stalling and trying to stay alive - then the RPMs shoot up. When it stabilizes, I begin to drive, and at first, I give it gas and nothing happens. Then all of a sudden, an immense power surge kicks in and the car rockets off. Once at a good 20-30 mph, it wil begin surging up & down, no matter how steady I hold the pedal. It goes away after a block or two worth of driving. It does this about every 3-5 starts.

Anyone here experiencing similar symptoms? Any suggestions? I'm apprehensive about taking it back to the dealer because I'm almost certain they're going to blame it on something else & try to squeeze me for a good chunk of my hard-earned cash. Especially since this never happened prior to the upgrade, I will then become very upset. All suggestions appreciated.

My 99 S80 (85k miles) does the same thing. ETM replacement was done. Cold start in cool weather results in stumble, lurch, stumble, lurch. Volvo regional service guy originally said that there was a software problem in the 1999 models that the software for the new ETM did not accomodate, but they were working on a fix. They applied that fix, but the problem persists.

When the car is warm, performance is not what it used to be either. Noticeable power loss during upshifts at full throttle, and some amount of unpredictable throttle response at all throttle openings.

Had the exact problems when I picked up my C70 for the etm update. Car almost died when I pulled it out of the dealership with tremendous amounts of surging. Drove back to the dealership and a day later and several hundred dollars later they replaced the maf unit. That was the last time I let the dealership touch the car. Personally I think they were full of S**T and ripped me off. All other dealerships I have dealt with give you an old part to show that they have been replaced. When asked for the parts they could not produce the old parts, hmmm sounds fishy. Try some maf cleaner first since it is inexpensive. Should have it on hand for maintenance purposes. If you need a new maf, buy one and put it on yourself it should take about 10 minutes.