EZK Wasted spark

//Original by Karl Buchka. Modded by blabla

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
uint16_t current = 0;
uint16_t lastcount = 0;
uint16_t average = 0;
uint8_t toothCount = 0;
uint8_t avgIndex = 0;
uint8_t firstRun = 2;
uint16_t lastFour[4] = {0,0,0,0};

int main(void)
{
    cli();
    _delay_ms(10); // Wait
    DDRC |= ( (1 << DDC0) | (1 << DDC1) );  //Enable PC0 and PC1 as output
    _delay_ms(10); // Wait
    DDRA |= ( (1 << DDA0) | (1 << DDA1) );
    _delay_ms(10); // Wait
    TCCR1B = 0b01000011;        // Rising edge input capture, Timer1 t/256 prescaling.
    _delay_ms(10); // Wait
    TIMSK = 0b00100000;     // Interrupt on Input Capture
    _delay_ms(10); // Wait
    sei();


    while(1) {
        //Do stuff
    }
}

ISR(TIMER1_CAPT_vect)
{
    // Rising edge only

        if (firstRun == 2) // First pulse, cannot calculate time between pulses. Just save captured TIMER value.
        {
        lastcount = ICR1;
        firstRun=1;
        return;
        }


        if (ICR1 < lastcount) {
            current = (0xFFFF - lastcount) + ICR1; // Counter overflow
        } else {
            current = ICR1 - lastcount;
        }
        lastcount =ICR1;
        // Second run of code, fill running average with first real tooth time.
        if (firstRun == 1) {
            for (uint8_t i = 0; i < 4; i++) {
                lastFour[i] = current;
            }
            firstRun = 0;
        }

        // Calculate average of last 4 non-missing teeth.
        for (uint8_t i = 0; i < 4; i++) {
            average += lastFour[i];
        }
        average >>= 1;      // Divide by 2

        // If missing tooth, zero tooth count, else (non-missing), check for trigger
        // teeth, add tooth time to running average, and increment toothCount.
        if (current > average) {
            toothCount = 0;
        } else {

            if (toothCount == 15) {
                PORTC |= (1<<PORTC0);
                PORTC &= ~(1<<PORTC1);
                PORTA |= (1<<PORTA0);
                PORTA &= ~(1<<PORTA1);
            }

            if (toothCount == 45) {
                PORTC &= ~(1<<PORTC0);
                PORTC |= (1<<PORTC1);
                PORTA &= ~(1<<PORTA0);
                PORTA |= (1<<PORTA1);
            }

            lastFour[avgIndex] = current;
            avgIndex += 1;
            avgIndex %= 4;

            toothCount++;
            average = 0;
        }

    }