hi got a m reg ls400 started to run rough misfire , put in new plugs new fuel filters got good sprk on ht leads but no joy still running rough like misfire any ideas thanks tony

 

HELP LOL running lumpy like misfire no power

 

o2 sensors. ? Or blocked cats.

 

Are you sure you have a spark on ALL cylinders? there are two coils on the LS400 one at the front of the engine and one on the driver's side of the engine opposite the battery tray, this one has caused problems before.
Another symptom is the cats glowing red hot when the engine has been running like this for a while.

Also is the timing belt OK not slipped a few teeth?

 

Any CEL? Clogged Cats like Steve said is first item to check. Next would be the 2 distributors on each cylinder bank