hi all .
i am in u.k
i have a 96 4.2 a8
last night the car started to misfire.
pluged in vag com .
turned out i have a cylinder 4 misfire .

today checked n.o 4 plug. it was soaked in fuel.
decided to swap cyl 4 plug and coil for cyl 1.
before doing this gave cyl 4 compresion test . got 155psi.
after swaping plug and coil over .started car and same problem .still a misfire on n.o 4 cylinder.
disconnected other 3 coil plugs one at a time and engine rev would drop.
checked for broken wires on n.o 4 coil plug and wire loom but found nothing.
checked for power at plug .3 wires in plug .got a positiv and negative at coil but the third wire was nothing.

not sure what to do .
please help

thanks
latif

 

You probably have a bad ignition control module. Follow the wires. They should go to a small box. Thats the control module.

 

There are two identical ignition control modules - try swapping the wires over - if the fault moves to cyl. 3, then the fault is with the module that was on the top (when you removed the plastic cover near the screen wash bottle).

Good luck.

Note that these modules can be repaired by opening them up and solering the bad connection, but the fix is not usually that permanent - I've had to re-fix mine 4 times in 120,000 miles - takes about 10 minutes each time.

 

Have you been able to get the cover off without breaking it? Every one ive done has broken. Do you solder the connection back together? Any pics? A writeup would save the guys on the a4 a ton of money but ive never been able to get the cover off in one piece which i believe would cause questionable realiabilty.