Engine Stop when decelerating

[Ryder]

Hi Folks.  I had to change the J12 power amplifier that feeds the coil on my 1991 3 litre petrol Shogun this week.  Trouble is that now when I am slowing down the tick over drops to 4000 rpm then lifts again to 8000.  This wouldn't be a problem but 6 out of 10 times it cuts out rather than stabalising.  General driving is perfectly smooth but I have no idea what would be causing this symptom.  Any ideas?

[mad geordies]

sounds like you have an air leak, check your vacum pipes to your manifild and breather pipes around that area

[Ryder]

Many thanks for the advice.  I have actually learned what the problem is and it seems quite common.  Having disconnected the battery when I broke down, the ECU had to re-learn how much fuel to deliver as I use the throttle.  The decelerating problem varies with temperatur and so takes longer for the vehicle to reset itself.  It took around 200 miles of varied driving, but it's fine now.