Getting ADC readings after waking a ATTiny85

I have this little project of mine that involves putting a ATTiny85 to sleep to save power. The main idea is to:

1- Putting ATTiny85 to sleep, including deactivation of the ADC
2- Wake-up MC on pin change
3- Activating ADC
4- Reading the voltage from the same pin that detected the change

The problem is that I'm unable to get a decent reading on the ADC after waking up the MC. It seems be to HIGH all the time.

Here is the code:

#include <avr/sleep.h>
#include <avr/interrupt.h>

// These constants won't change.  They're used to give names
// to the pins used:
const int analogInPin = 2;
const int LED = 3;

volatile int outputValue = 0;

void setup() {

  pinMode(LED, OUTPUT);
  pinMode(analogInPin, INPUT);

  digitalWrite(LED, LOW);
  digitalWrite(analogInPin, HIGH);

}

void MCSleep() {

  GIMSK |= _BV(PCIE);                     // Enable Pin Change Interrupts
  PCMSK |= _BV(PCINT2);                   // Use PB2 as interrupt pin
  ADCSRA &= ~_BV(ADEN);                   // ADC off
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);    // replaces above statement

  sleep_enable();                         // Sets the Sleep Enable bit in the MCUCR Register (SE BIT)
  sei();                                  // Enable interrupts
  sleep_cpu();                            // sleep

  cli();                                  // Disable interrupts
  PCMSK &= ~_BV(PCINT2);                  // Turn off PB2 as interrupt pin
  sleep_disable();                        // Clear SE bit
  ADCSRA |= _BV(ADEN);                    // ADC on

  sei();                                  // Enable interrupts
} // sleep

// Whatever the pin this IRS should always point to the PCINT0_vect, because is the only capable of
// providing the interrupt. The ISR must be provided otherwise, the MC just resets instead of resuming.
ISR(PCINT0_vect) {

  // This is called when the interrupt occurs, but I don't need to do anything in it
  delay(100);

}

void loop() {

  MCSleep();

  delay(100);

  outputValue = analogRead(analogInPin);

  if (outputValue > 100){
    digitalWrite(LED, HIGH); // Door is open.
  }
  else{
    digitalWrite(LED, LOW); // Door is closed.
  }

  delay(200);
}

From the ATTiny85 specs it seems that after reactivating the ADC there is some extended conversion, so I tried to add a delay after waking up (which didn't work) and later on
I've tried to implement some other ideas like saving the ADCSRA value before sleeping and recover it after waking up, but unfortunately, that hasn't work either.

#include <avr/sleep.h>
#include <avr/interrupt.h>

// These constants won't change.  They're used to give names
// to the pins used:
const int analogInPin = 2;
const int LED = 3;
byte keep_ADCSRA;

volatile int outputValue = 0;

void setup() {

  pinMode(LED, OUTPUT);
  pinMode(analogInPin, INPUT);

  digitalWrite(LED, LOW);
  digitalWrite(analogInPin, HIGH);

}

void MCSleep() {

  GIMSK |= _BV(PCIE);                     // Enable Pin Change Interrupts
  PCMSK |= _BV(PCINT2);                   // Use PB2 as interrupt pin
  keep_ADCSRA = ADCSRA;
  ADCSRA = 0;
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);    // replaces above statement

  sleep_enable();                         // Sets the Sleep Enable bit in the MCUCR Register (SE BIT)
  sei();                                  // Enable interrupts
  sleep_cpu();                            // sleep

  cli();                                  // Disable interrupts
  PCMSK &= ~_BV(PCINT2);                  // Turn off PB2 as interrupt pin
  sleep_disable();                        // Clear SE bit
  ADCSRA = keep_ADCSRA;

  sei();                                  // Enable interrupts
} // sleep

// Whatever the pin this IRS should always point to the PCINT0_vect, because is the only capable of
// providing the interrupt. The ISR must be provided otherwise, the MC just resets instead of resuming.
ISR(PCINT0_vect) {

  // This is called when the interrupt occurs, but I don't need to do anything in it
  delay(100);

}

void loop() {

  MCSleep();

  delay(100);

  outputValue = analogRead(analogInPin);

  if (outputValue > 100){
    digitalWrite(LED, HIGH); // Door is open.
  }
  else{
    digitalWrite(LED, LOW); // Door is closed.
  }

  delay(200);
}

Any ideas?

Thanks in advance.

So, apparently, if I use pin 3 (PB3) instead of 2 (PB2) as the interrupt pin, I get decent readings after reactivating ADC. Still have to find out why!