Random drop in idle on Citi golf 1.4 mpi

[Mischief Maker]

Hi Guys - me again! Have a 1.4 citi golf mpi 2009 with +163 000 kms on the clock- the car seems to drop it's idle randomly and then picks up back to a 1000rpms. It drops down to about 400 or 500 and then picks up.

I have changed the following-
1. Fuel filter
2. Cleaned throttle body
3. Did adaptation to the TV

What else could be the problem ?

Help pls !

[panic-mechanic]

the mpi is the problem. You will waste thousands of rands and days out of your life to solve it which you won't.

[Mischief Maker]

Why ? Please elaborate

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[Mischief Maker]

I have had many mp9 without any problems - what is going on with mpi - pulling my hair out here ...basically the entire car had been fitted with brand new parts from front to back ...I'm now thinking it could be the temperature sensor ... your thoughts ?

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[panic-mechanic]

because they are crap. I don't know why. I have had about 8-10 of them here in the last year - it starts showing random faults mostly one which says lambda open or short to ground. Once the thing does that you can change sensors and try whatever you want it will randomly change the fuelling from lean to stupid rich each time it does this the idle falls or changes.
I think it burns a circuit inside the board.
The only way I have fixed this was to stick it on aftermarket management.
But yeah contine trying to fix it and let us know if you find a miracle simple solution. I tried. Changed every single sensor and it made not difference to the outcome.

[Mischief Maker]

Gees man - thanks for the heads up - let's hope for a miracle.

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[Mischief Maker]

because they are crap. I don't know why. I have had about 8-10 of them here in the last year - it starts showing random faults mostly one which says lambda open or short to ground. Once the thing does that you can change sensors and try whatever you want it will randomly change the fuelling from lean to stupid rich each time it does this the idle falls or changes.
I think it burns a circuit inside the board.
The only way I have fixed this was to stick it on aftermarket management.
But yeah contine trying to fix it and let us know if you find a miracle simple solution. I tried. Changed every single sensor and it made not difference to the outcome.

Hi Panic - mechanic - what am I in for if I want to go the after market route ? Plus minus avg cost and time frame ?

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[panic-mechanic]

it all depends on what you get and where you get it done.
I don't pull the stock system out and leave it to do idle control which it does just fine when it's not controlling timing or fuel. So I basically steal the injetors and coil away from the MPi and leave the rest.