Technical engine anti stall

[FASTMOGGY]

Still running my elenganza 1.2 05 plate. which suddenly didn't want to start straight away this morning after it had been stood for 4 hours which was quite scary as I had problems with the crank sensor a few years ago!
Car started so as it was low on fuel I filled it up with the 'good stuff' 97% and a dose of redex just in case it needed a bit of a clean out.
Now ive noticed if I rev the engine up (when warmed up) the engine goes to an almost stall with the rev counter dipping to around 500rpm before the engine corrects its self and goes back up to 800.
Question is,as its just started to go below freezing here and the tank was neigh on empty, could there be some condensation within the fuel tank causing this problem or is there something more specific going on?
As for the redex, the car does get a dose every now and then with no running issues.

 

[DaveMcT]

My 100HP has been doing this recently. I changed one ignition coil and it improved but the problem has returned so I have ordered three more new coils.

The 1.2 has two twin spark coil packs. It's likely that one is failing. A fault code reader might give some clues but if it's intermittent you may not see anything useful. New coils cost about £20 each but £40 is a lot to pay when the fault is eleswhere.

MES running on a Windows Laptop can data-log the engine data so that would be the best way to diagnose your problems. Costs are £30 for a decent quality OBD cable connector and the free software version may well be enough. Registered version with a few more features is about £45.

 

[FASTMOGGY]

Yes, the ignition coils were a firm favourite, BUT all of a sudden she's running as normal.
I have had issues in the past with 'suspect' petrol from one particular filling station I use occasionally and no where else which gives the engine a 'lumpy feel' especially when on tick over hence my thinking contamination in the fuel. Now she's full of 'jet fuel' or 97% she's back to her normal self. At the moment there is no engine management light on so I'm not sure if the fault at the time would be recorded?
On a final note, there's a good reason why I call my car Marmite. She either runs sweet as a sewing machine or on the odd occasion ('s) gives me minor palpitations when she goes into sulk mode! LOL
In in all shes a good car and not long past her MOT with no faults or advisories.