Hello, Glad to find this forum, I've not had my 97 Blazer too long but have loved it and have lots more work to do on it to make it even better...

Yesterday when I went to start it, it (first couple times) would rev up over 3000, then down to almost stall out and then back up. After about three times of this, while I was beginning to look for a leak in the intake system, it changed and would rev straight upwards on start and the rev limiter killed it. So I can't check for leaks like I wanted to with the carb cleaner.

I have checked the linkage to the butterfly and it all looks good, and since I can't get it out of the driveway now, I haven't been able to check any codes. Unfortunately, it was on before this all happened because I know I have a bad O2 sensor, so I didn't have warning per se.

Any ideas on what I could check next for lack of getting codes checked? I have checked around forums and haven't found any similar problems or anything in the DIY section, but I could be missing it.
Thanks!