Hello gamm_84, to see if it will turn out that it bathes the spark plugs for a problem with the fuel regulator, you should measure the pressure on the injection ramp (at one end of this) it works to about 3 bar. From pressure to idle, then (in some models) they mount an auxiliary air valve between butterfly and injector body, if this fault can have to do in the fuel. In any case, Code 33 that affects the speed sensor, this is mounted on the transmission, generates 4 impulses per differential turn (in manual boxes), the ECU corrects the amount of fuel injection, depending on the vehicle speed, butterfly position, refigrant temperature, and others ... so I think you should look at this sensor or its wiring. Greetings!!