91 300E CEL came on, went off - runs fine ???

[gmercoleza]

91 300E in very good condition with 124,000 on the clock. Check engine light came on briefly today. The car was warm at the time, but had been sitting about an hour in 70 degree weather. After the hour of sitting, I got in with some friends and drove semi-aggressively in order to keep up with another car we were following. After about 30 seconds, the CEL came on - I had never seen it before, so I didn't know what it was until we stopped approximately 5 minutes later. Total drive time was about 5 minutes, then I turned the car off. When we got back into the car an hour later, I started it up and the CEL was not on anymore. So far, have driven another 20 miles tonight and no sign of the CEL.

I just did a search and found a few really helpful threads regarding CEL diagnostic codes and what they mean. My question is: do I need to start troubleshooting the cause of the CEL light yet? It only came on once very briefly and isn't on anymore. Should I wait to see if it comes on again and then worry about it?

I bought this car almost 3 months ago, have put on over 6,000 miles without any problems whatsoever. I have the typical intermittent high idle which I mentioned in another recent post (1800 RPM in neutral, about 1000 in gear) and it occurs maybe 1/3 of the time - the other 2/3 of the time it idles flawlessly. I just haven't gotten around to checking into the high idle; Duke mentioned the TPS and I was going to check that this weekend, but due to busy schedule it looks like I won't get to it until the holiday weekend.

Could the high idle have anything to do with the CEL? Could it have been caused by my somewhat aggressive driving without allowing the car sufficient time to warm up? I mean, I was pegging the gas right after startup, but it's not like the car was cold or anything - it still had a fair amount of temp on the gauge. Is the car still safe to drive? It sure runs fine, and it ran fine even while the CEL was on (wasn't experiencing the high idle at the time).

Can anyone provide any advice? I'm starting to get paranoid; maybe my pleasant-running car is about to turn on me...

Thanks!