Pigpen1204

Little background:
1998 Camaro 3.8 m5
Having a small misfire issue on cyl. 5 (unrelated i think)
every now and then the car runs like a champ and every now and then it misses badly but is still drivable as long as i dont gas it to much and take my time accelerating.

This morning was one of the in the middle days where the car has a minimal ammount of hesitation and is running decently. I pull out of a stop light (getting ready to get on the highway) and I push the clutch in to shift into second and BAM RPM are redlined and the car is racing. I shut off and rolled to the shoulder. I started it on the shoulder and wooosh the car is racing(were talking 6k RPM instantly). So i quickly shut it off. Only thing i can think to do on the side of the road is get out and play with the throttle to see if its physically stuck. It wasnt. I opened and closed it a few times quickly by hand (Just pulled on it) got back in and was able to make it to work. I imagine ill have more info after i drive'r home for lunch, but anyone seen this before? Any thoughts?
Thanks
--Pigpen1204
(Everett)