2.1 mv power loss at speed

[bodgit]

intermittant prob just started.can be driving at 60 and just let foot off to change up to fifth and power loss is instant.if nobody was behind i could keep light throttle and it gradually came back,no good stomping on throttle-no difference.virtually undrivable,however if i switch to lpg it is fine!just replaced idle control valve,put injector cleaner through tank-no other changes.anyone been through this?any ideas if this is electrical or fuel delivery.
van idles fine on lpg or petrol and seems to rev well when not under load .any help appreciated but am away from computer in week so not being rude if i don;t reply

[Red Westie]

I had a similar fault last year with an intermittant power loss and I mean nearly to a stand still with the engine rough as out boots.
Turned out to be a failing lambda sensor in the CAT. This can be easily diagnosed as it can be unplugged in the engine bay when the fault occurs (engine hot) and if your power instantly re-appears you have your culprit.
Martin

[bodgit]

thanks for that.will give it atry.hoping to dump cat when i fit a replacement engine soon...am assuming lambda sensor aint cheap and will be rusted solid to cat!