My 2004 A4 1.8T, BEX engine, has developed a missfire on cylinder 1 (as confirmed last night by the AA) with the engine management light flashing. It happens typically when driving up a hill under load. The car has had new coilpacks (courtest of Audi) and new spark plugs in the last 200 miles approx.
While the AA chap was out, we swapped first the coil pack and then the spark plug from number 1 cylinder with some spare ones I've got, cleared the fault and went for a drive to find that the fault was still there both times. So that seemed to rule out the plug & coil pack.
As a further check, we swapped the plug & coil from cylinder 4 to cylinder 1 and put the original cylinder 1 coil & plug in cylinder 4. We expected the fault to still be present but it didn't re-occur and no fault codes were logged on the test drive.
There's no reason for it to be fixed so I'm expecting it to re-occur.
Does anyone have any suggestion as to what else it might be, please?
The same thing did happen last year but I thought then that a faulty spark plug had caused it as it went away when a plug was swapped out. Maybe that was coincidental and there is an underlying fault?
Thanks in advance and sorry for the lengthy post!