Mis-fire When Hot.

[zaph]

Our LS400 after a considerable journey of 150 to 200 miles - mostly motorway - will misfire/run rough, if left after 20 or 30 minutes or so, and will only clear after welly to the floor, to about 3k revs, and around 200 yards, and then be fine all day thereafter. Some occasions I can stop after another 150 or 200 miles, return again after 20 -30 minutes, and she'll start first time on the button (as always) and everything is fine.

I'm thinking fuel evaporation.

Any other thoughts?

[Haylands]

Our LS400 after a considerable journey of 150 to 200 miles - mostly motorway - will misfire/run rough, if left after 20 or 30 minutes or so, and will only clear after welly to the floor, to about 3k revs, and around 200 yards, and then be fine all day thereafter. Some occasions I can stop after another 150 or 200 miles, return again after 20 -30 minutes, and she'll start first time on the button (as always) and everything is fine.

I'm thinking fuel evaporation.

Any other thoughts?

Hi

Just a shot in the dark, could be leaking fuel injectors, when you switch off after a long run, the injectors leak petrol into the engine causing it to flood untill you welly it to clear it through. First thing to do would be use some injector cleaner and see if it makes a difference.

Good Luck

Pete

[zaph]

Our LS400 after a considerable journey of 150 to 200 miles - mostly motorway - will misfire/run rough, if left after 20 or 30 minutes or so, and will only clear after welly to the floor, to about 3k revs, and around 200 yards, and then be fine all day thereafter. Some occasions I can stop after another 150 or 200 miles, return again after 20 -30 minutes, and she'll start first time on the button (as always) and everything is fine.

I'm thinking fuel evaporation.

Any other thoughts?

Hi

Just a shot in the dark, could be leaking fuel injectors, when you switch off after a long run, the injectors leak petrol into the engine causing it to flood untill you welly it to clear it through. First thing to do would be use some injector cleaner and see if it makes a difference.

Good Luck

Pete

Thanks, Pete.

Hadn't thought of that. Doh!

I'll be giving that a whirl.

[ManicMark]

Hi

I had much the same problem with a mazda 626 I owned, it turned out to be a loose eletrical conector on one of the injectors

( I spent a small fortune on new leads, plugs , injector cleaner, maf sensor, before I stumbled across it)

its worth a try and its a free fix if it works.

best of luck Mark