Running like a bag of nails.
 

In addition to other maladies, I am now suffering a horrible intermittent misfire. When it happens idle is lumpy and cruising at any speed is jerky and erratic. Acceleration is similar and is obviously off power. I now have VCDS but have yet to understand how to use it.

This misfire doesn't happen all the time but when it does it's very annoying. If anyone knows where I should start looking I would be grateful.

Ta

Steve

You need to put your car details on your signature tag, helps folk know what engine you have! ;) Coils are not an uncommon failing point and would produce a lumpy idle, a loss of power and jerky throttle response. On a V6 the coil is 1 large block of 3 dual firing coils and a failure will knock out 2 cylinders and will be very obvious. I don't know about older v8's (they may be on double plug coils) but a quick search on the forum suggests for the V8 the coils are individual with 1 coil on each plug, the results will therefore still be felt but to a lesser degree (6cyls to 4cyls vrs 8cyls to 7cyls). There are many things that can cause misfires but if it's intermittent it could be the coil breaking down internally as it gets warm. Best of luck chasing down your gremlin!

VCDS is very straight forward. For missfires go into "01 Engine",
Click on the "Fault Codes" button, this will scan for any engine fault codes.
If there are no fault codes, go into "Adv. Meas. Values".
A list will pop up with lots of tick boxes. They are pretty much self explanatory. Scroll down the list and tick the ones you want to display. For missfires, tick each cylinder individually and watch (with engine running) which one registers the missfire. Then you will know which cylinder is causing the problem.

Thank you chaps for that very useful information. I'm without the car for the time being as one hour after I started this thread a drive shaft went kaput, so I've hired a car for work for the time being. (it doesn't rain. It only pours!). When I get home this weekend I'll follow your advice, Goran, and see what I can come up with.

Thanks guys

Steve

I'm going with "Multi cylinder misfire" as a fault