I recently took my 1996 SSEi to the dealer for a relatively minor repair, and when they hooked up their scanner they came up with all sorts of codes indicating problems that I wasn't even aware of. It pointed to weakness in the ignition module and the crankshaft position sensor, which they replaced. The point is: I would have preferred to know this myself and not be driving a time bomb.

What'* the best way to uncover not just the ODB II, but all the enhanced diagnostic info (and more, if there is such a thing)? I'm thinking something that I hook up to a laptop, like the autotap:
http://www.autotap.com/autotap_for_windows.html

There seem to be a lot of these types of diagnostic softwares out there, so maybe there'* something better or cheaper I should consider. Mostly, I want to know if there are pending problems, and if so what they are. Also, it would be nice to capture baseline performance data so that I can compare over time to see what parts might be failing before they actually generate codes. Is there anything that does this in an easy-to-use package? I hear some of these things even compute MPG, but I'm not sure how accurate they are. If they are accurate, then it would be good to measure this (instantaneous as well as average), so that I can perhaps modify my driving habits accordingly. Any strong recommendations?

i know Kyle has a autotap that is connected to a Palm...It showes all kinds of info, and you can view 4 different sets of data at once....i believe he got his from Intense-racing.com....the Actron 9145 is also a good tool that can stream data but cannot record....both of the tools mentioned can pull DTC'*....these are not the only options out there for scantools

Beyond reading error codes, which performance metrics do people here typically find most useful to look at when they hook up their scanner?

I'm the family wrench. Got an otc genisys. Reads sensors, ignition, everything but don't have the abs cartridge yet. It gives codes and possible causes.

Some of these scanner will report instantaneous miles-per-gallon if you run the car while it is connected. Anyone know how accurate that might be? e.g. within 5%, 10%, 20%, 40%? I might pay up for one that can do this if it has some decent accuracy.

I had posted a similar question in the electronic/electrical section...didn't receive any responses. I'm looking for a laptop based one, and was comparing between the Digimoto, and the Autotap, amongst others. At this point, I'm leaning toward the Autotap.