Also posted on SwedeSpeed and TurboBricks

Gentlemen (and Ladies?),
I drive a 2006 S60R with 6 speed auto. Yesterday, I was driving home and the engine started to hickup a bit on the highway. It did it for maybe 5 seconds (on cruise) and then returned to normal. Of course, I needed to drive to Cleveland that night (from Pittsburgh), so I was mildly concerned, but made it to Cleveland without incident.

Coming back this morning, I had significant problems and consider myself lucky to have made it home. The engine had lots of issues, including up to 10-15 seconds of no power (coasting down from speed with engine downshifting) and no response to throttle. At one point, I started to pull off onto the shoulder at maybe 30 mph when power returned aggressively (yes...I was flooring it in vain trying to make it do something). During this time, the gauges all worked, as did the interior displays etc. It just felt like I had turned off the ignition to the engine.

Luckily I made it home and then plugged in my scan tool (Innova 31603). There are no codes thrown or pending. As such, I started looking at live data. I found that if I held the throttle steady at 3000-3500 RPM, it would run smooth then cut out for maybe 300-500 RPM, then come back up etc. This would occur pretty rhythmically every 3-5 seconds. Usually after several of these (maybe 10-15?), it would drop to above idle without me moving my foot. If I pushed the gas in further, or just let off and got back on the pedal, I had no problem repeating the behavior over and over.

These cuts corresponded to a TPS readout changing notably (not a complete cut out, but maybe 25-30% of the range). Additionally, Narrowband went lean for these and spark advance went from 30ish to -5 or so. However, just blipping the throttle up and down seemed to reproduce this O2 and Advance behavior, so I am leaning towards saying those are not indicating anything. Also, fuel pressure is absolutely perfect throughout all of this, so I am pretty convinced it isn't a fuel issue.

Sooooo...my thoughts:

I've had cam position and crank position issues on a 98 S90, and don't think it really feels like that. I never lost power with those, just had false rev limiters. I believe the fuel system appears sound. There were no pops or backfires when I lost power (which I'd expect with a full loss of ignition), so I am leaning towards an ETA issue. However, I am not a real expert in these cars, so please tell me where I'm wrong. I'd appreciate any help you can give. Thanks in advance!

P.S. I have noticed occasional hiccups (felt like a single misfire) going up hills on cruise for maybe a year now. I never thought too much of it...but it is worth noting. I also think most of my hiccups today happened going up slight grades.

 

Any idea how much hidden info I can't see with a generic (albeit higher end) scan tool? Is there a good chance VIDA would have stored, pertinent info I can't see?