won't start because of immobilizer
So to make a short story short, i have a 2001 is300, its ran and drove fine never had any issues with it.
what started this all was i was leaving my house then 2 mins after pulling out down the road car started to bog out for a moment then went to full RMP's then straight cut off.
so i figured it was the full pump since it did start again with starter fluid. got a new fuel pump installed. still didnt start. but then i noticed it wouldnt start no longer with starter fluid.
did more research, replaced igniter as well, all relays were checked and replaced. FP relay was replaced as well. all fuses checked and replaced. still nothing worked.
car has 2 keys 1 flat key which was in that switch kind if fob. but fob still locks car and everything like it should. 2nd is key with fob attached original key (black not grey) works perfectly as it should.
security light continues to blink even when key was put in. so i did some searching around and tried to reset immobilizer by disconnecting the battery bother terminals and then inserting the key onto the ON position then reconnecting battery to reset. well the FIRST time i did this it worked. security system was no longer active and light was off. car wanted to start but battery was a bit weak at this point. so i charged it and then went to start the car, to only notice that the security system was tripped once again and immobilizer wasn't coming off. so i then tried again to get the system to reset and it wouldnt, i tried another 15x or more and nothing.
i am so confused on what the issue could even be at this point.
any tips, tricks or a point of direction would be great
* and ive also looked into multiple forums, posts, and this issue, nothing has helped*