Rookie ILS question

Hi All,
I'm a rookie but I have already performed a dozen succesfully ILs landing with Learjet and Bombardier therefore I know the procedureand how to handle the aircraft before touching down.
Now with 737s I can land safely but several times the ILS completely miss the runaway even if every single time I use the same procedure.
I have the Deluxe edition with SP2,do you know if there is any bug or " meteorite random failure " that I forgot to switch off ?
I am astonished how many times the ILS fails the approach despiting several other times it let me land safely.
I do :
1 ) @ around 30 nm I request to land and I acknoledge
2 ) @ around 2500 feet I switch to from GPS to NAV
3 ) I turn the APP on
4 ) the tower give me the clearance & I acknowledge
5 ) 3 green on on my gear
6 ) 70-90 % flaps and 170-180 kias
6 ) around 500 feet I disengage the AP and " gently " I touch down
Sometimes as soon as I switch from GPS to NAV and just after I turn the APP on the plane gets crazy climbing till stall or do fireworks in the sky. Recently this happens 50% of the times I approach,strange cause I have done a dozen succesfully landings.
So the problem is not landing that it is quite " weird " on FS anyway it can be handled by the mouse with no particular problems.The issue is the ILS that often get crazy crashing the plane.
Is there any hidden feature ? It's not the weather indeed.
THANKS guys
P.S. I forgot to say that my FP leads me directly every time into the glideslope with no turns. In addition the NAV 1 is properly activated on the correct runway frequency and I can hear the MORSE.
I'm a rookie but I have already performed a dozen succesfully ILs landing with Learjet and Bombardier therefore I know the procedureand how to handle the aircraft before touching down.
Now with 737s I can land safely but several times the ILS completely miss the runaway even if every single time I use the same procedure.
I have the Deluxe edition with SP2,do you know if there is any bug or " meteorite random failure " that I forgot to switch off ?
I am astonished how many times the ILS fails the approach despiting several other times it let me land safely.
I do :
1 ) @ around 30 nm I request to land and I acknoledge
2 ) @ around 2500 feet I switch to from GPS to NAV
3 ) I turn the APP on
4 ) the tower give me the clearance & I acknowledge
5 ) 3 green on on my gear
6 ) 70-90 % flaps and 170-180 kias
6 ) around 500 feet I disengage the AP and " gently " I touch down
Sometimes as soon as I switch from GPS to NAV and just after I turn the APP on the plane gets crazy climbing till stall or do fireworks in the sky. Recently this happens 50% of the times I approach,strange cause I have done a dozen succesfully landings.
So the problem is not landing that it is quite " weird " on FS anyway it can be handled by the mouse with no particular problems.The issue is the ILS that often get crazy crashing the plane.
Is there any hidden feature ? It's not the weather indeed.
THANKS guys
P.S. I forgot to say that my FP leads me directly every time into the glideslope with no turns. In addition the NAV 1 is properly activated on the correct runway frequency and I can hear the MORSE.