Misfire / noisy exhaust?

[NWTony]

After my trivial problems with keeping alacantra clean, I've developed something more serious...

Engine feels like it is misfiring although it starts OK and after a short distance I start getting a metallic banging / shaking noise from the rear of the car. I hasten to add I haven't been driving it in this state!

Any thoughts?

[shep1001]

NWTony said:

After my trivial problems with keeping alacantra clean, I've developed something more serious...

Engine feels like it is misfiring although it starts OK and after a short distance I start getting a metallic banging / shaking noise from the rear of the car. I hasten to add I haven't been driving it in this state!

Any thoughts?

Diff maybe or U/J? or is it deffo the engine ie does it do it when stationary?

[NWTony]

It struggles when stationary yes. I'm presuming (hoping) that it's a relatively simple misfire that's causing the engine to rock, which is knocking the exhaust. The car did tend to vibrate through the chassis (rather than through the steering wheel) at high speeds (85 ish) before this but I'd put that down to rear wheel balance as suggested in the speed 6 bible.

[Waitey]

Have the exhaust mounts sagged? Mine went last week and now the exhaust sits on the number plate surround and it makes one hell of a racket.

The mounts are a few £ from TVR power.

[NWTony]

Misfire was a bugger to diagnose, went through the plugs, leads and coil pack. By process of elimination it was isolated to 1 and it wasn't any of the above. To cut along story short it turned out to be the lead to the switch on the injector on 1, you can imagine how long it took to eliminate all the other potential causes before reaching that one.

Fixed in the end The exhaust noise was symptom of the misfire, it must have been knocking. I did discover that the garage that did the 12 month service had basically glued the plug cover in place with about a tonne of sealant / adhesive. That took some shifting I can tell you, especially daunting since in the end it wasn't required.

All's well that ends well. Thanks to all for suggestions and help.

PS I also discovered that scrap yards don't have many V6 Omegas in...