Hi have a OBD1 ABA with a 276 cam and a chip from Techtonics Tuning.

My problem is: When I cold start the engine, it takes some time before it finds a stable idle and after a minute or see it does and when I take off everything's alright. But if I take of before it, when I clutch to change a gear, the engine starts revving at around 4000 rpm for a second before it goes back to idle.. For example, if i change gear from second to third at 3000 rpm, it'll starts to rev to 4000 or so rpm for 1, 1.5 second before going down.. It's not the computer because it does it with 3 different ones.. I was thinking about the crank sensor..? Anyone has a clue?