Cranking OK but NO Start, Crank Shaft Sensor Did'nt help

[Lubi]

Hello Guys,
I am a new owner of Clio Mk2 1.2 L D7F I4l, I got the car as a gift in ideal condition, and I am starting to love driving it, it's fun except there are issues that concern me. Hopefully, you guys will be able to help me.
Sometimes the car won't start "Cranking OK but NO Start" After reading many forums & watching several videos, I Pulled out the crank sensor and cleaned the tip (Which was dirty indeed), it's still magnetic, but unfortunately no change in the problem.
Several days ago I got stuck very badly & the car Revved up only after the 8th try.

I am an Aerospace engineer who loves to get hands dirty with my cars, My previous car was a Suzuki Swift which I maintained & serviced myself, I mean if the problem is not something of a super-advanced level then I have the tools & ability to fix it + I would love to know my CLIO inside out just like my previous cars. In short words, I want to know & learn this french baby inside out.

Thanks in Advance to everyone.

 

[Matt Cup]

So you just cleaned the original cps? Perhaps you just need to change it for a new one instead.

 

[Lubi]

Yes, i just cleaned the original cps (BOSCH brand), I'll check if I can find a new one.
However, I might have run into the root cause of the problem by chance. An hour ago the "Crank & No Start" problem happened again but before this happened I noticed that the red Light🚨 (I guess its the immobilizer light) on the instrument panel was flashing FAST & then when I tried to start the car, the "Crank & No Start" happened. I removed the keys & put it back in, turned the ignition, the red Light on the instrument panel was not blinking anymore then i Cranked & engine came to life immediately.
Maybe this "Crank & No Start" problem is related with this Red blinking light on the panel.