Hello honda-tech.com users

I have a problem with my 93' Prelude's H22A2 VTEC engine (no upgrades).

Yesterday I tested my car on racetrack.

After a little brake I started accelerating to the maximum. On 3rd gear, when I reached 3.5K rpm, the engine didn't let go highier (engine turned into SAFE mode).

Before this problem the check engine lamp showed code nr. 12 (EGR system) but I didn't feel any problem with the engine.

Now the check engine lamp shows one more code-> 4 that means the following: CKP Sensor{2} & Vacuum Switch{1}

Did anybody have a similliar problem & how serious problem this could be.
Any suggestions what do I have to start checking with?

Tnx a lot