Modernish distance fault diagnosis

[DodgeRover]

Returning from a 200 mike motorway run in the Lexus RX300 was running fine till we stopped at the services, then after getting back on the motorway it's way down on power, sounds and feels like it's on 4 out of 6 cylinders?

Fault is the same on petrol or gas, wierd thing is the inboard fuel computer says economy has improved by about 10mpg to over 30 pushing it hard trying to keep it going up hill, over the last 30k it's never averaged better than 25.

Could it be the MAF sensor that's had a wobbly?

Am checking plugs tomorrow when it's light too.

Other than coil packs any more ideas?

Emisions were fine for mot this morning.

Thanks muchly

[spartacus]

Do the gas injectors use a pulse from the petrol injectors to fire? If so, it might be wiring to one or more injectors, the fuel computer may take a signal from them to calculate fuel used but the ECU may have shut them down on sensing a fault, to prevent cat damage.

[DodgeRover]

I think ECU had a moment and shut down some cylinders. Went out this morning reset fault codes by removing ECU fuse and it's perfect, been for a drive and CEL is back on (as it always is while it's on gas) but no sign of misfiring on either fuel.

Weirdness, hopefully new plugs on Monday will reveal silly gaps or some such