Check Engine Light P1334 on 2000 9-3 Viggen

My wife took a 100 mile drive today for work and from 30 miles in experienced a bit of stuttering in the engine, particularly in 3rd gear, and a check engine light. Once we got the car home in the driveway I hooked up my OBD II Sensor and found code P1334. I cleared it and it stayed gone while I listened for valve issues and to the sound of the engine trying to hear anything unusual. I then shut off and started the car several times in succession and managed to bring the light back.

I have gotten the general idea that this seems to point to the DI Cassette, but before I order a $250 part I was wondering if anyone has any pointers or ideas... things I should try?

Some facts:

• At idle when sitting the engine revs drop from ~900 to ~500 for a second when the fan kicks on. This seems unusual to me as when the issue first occurred it seemed like the car was going to stall. This began over a year ago and hasn't seemed to cause any issues since.
• Spark plugs were replaced in June 2012 with the recommended plugs from Genuine Saab.
• Oil pan was dropped in April to be cleaned out while the transmission was out for the new clutch. In the oil a small plastic piece was found. The only thing my mechanic could think of was a piece of the timing chain guide.
• The car has 187k mi.
• The oil pump sprung a massive leak two years ago, the belts, pulleys, and pumps were all replaced.
• The coolant temperature runs about 212°F, when sitting idle it can hit 235°F.

I just did a clutch on the car which set me back $7k out of my $3500 allotted budget. I really don't have a lot of money and I would rather not get my mechanic involved unless need be. All I would like out of it is to stay reliable to 200k when the wife and I have agreed to retire it until it can become a rebuild project on the weekends, but it is probably going to sit for quite a while since before starting a rebuild project a house with a garage is required.