Mega flat spot - 156 twinspark

[156Buck]

2001 156 TS manual- done 115,000km

For a while on almost every cold start my car has a flat spot below 3000rpm, where there is little power and an extreme reluctance to rev. No matter the throttle position it will slowly build to 2500rpm, where it feels like the engine hits a wall for a second and then explode past and accelerate normally between 3000-7000.

Recently, out of no where it refused to idle one day and lost all drive ability. I reset the ECU (disconnect battery etc etc) and it fixed that and even seemed to drive better then before, sometimes even regaining all drive ability on cold starts!!
but now it seems to be getting worse, becoming more temperamental on cold starts and even backfiring (or knocking? but really unsure) occasionally.

I suspect its the Idle control valve, due to the idle issue and on a very brief call to an alfa indie they claimed it was the culprit.  I know it there are possibilities in the MAF and lambda sensor being to source or contributing to the issue. but im just curious if anyone has experienced anything similar and can shed some info please?

Thanks in advance
Jake 

[colcol]

Hello Jake,
Take it back to the Alfa Romeo Independant Service Provider and have it scanned to pin point the problem you are having, as opposed to guess work offered over the internet, without looking at the car, Colin.

[Mick A]

Hi Jake,

Based on the information you have provided and without actually being able to see the car I would make an educated guess and suggest you replace the Airflow Meter.

It will most likely either be that or a split in the intake pipe after the AFM, letting un-metered air enter the engine.
But more than likely it's the AFM. Your description has all the symptoms.

Cheers. Mick.

[156Buck]

You were right Mick! Turns out the MAF was on its out, now it revs clean to redline 
Thanks everyone