Evening all. I've been Googling around for information about this problem and although I've come across a couple of accurate descriptions of the matter an allusions to potential solutions I thought I'd run it by this forum to see if anyone salutes.

We've bought a 1996 Autohomes Camelot on a Ducato/Talbot base on the strength of having previously owned exactly the same model a few years older a while back but this one is exhibiting one particular vice that its predecessor, with an additional 30k on the clock, did not; when asking for a bit more power under load the engine starts to cut out at higher revs and power is lost. The van judders and gear stick wobbles. Dropping down a gear to obtain less torque works until higher revs are reached again (usually only a matter of seconds) and the process repeats. The same dropping through to second and first in extreme cases. When running on the flat the van happily trips along at 60 in 5th. It could be fuel starvation, it could be exhaust exit pressure, it could be an aeration problem. It's not a misfire and it's not a throttle pedal sensor issue as the throttle is cabled. As I said, the previous van did not do this, it was sweet as a nut, so I know that its not normal engine behaviour. One observation that may be relevant is that the van was parsimonious on fuel on its first trip. We only used £40 in fuel on a trip into Mid Wales from the Peak District and that has caused me to direct my mechanic to the carburretor. He's already had it on the sensors and the mixtures and emissions are all bang on. The plugs and leads are also brand new which leads me to believe that the previous owner had this problem, tried to solve it by having it tuned and failed so got rid. I'd sooner not get rid simply because the van is absolutely ideal for purpose and I know that it shouldn't behave in this manner.

Your suggestions, philosophies and experiences are welcome.

Cheers

Chris

A bit of an update on this one....

The mechanic reckons that its actually an electrical fault. It may be to do with the age of some of the circuitry but the it seems that its ability to serve the amount of charge required by high revs is compromised. He's putting in a charge amplifier to see if it works. Sounds plausible....

Just got the van back from the garage. The charge attenuation theory was rubbish so they pulled the carb out again and re-examined the fuel line. Suprise, the fuel filter was gunked to buggery:bang:. They'd missed it because the filter paper is rust coloured (!design fault!) and when they took it out a load of mud came out of it. Under high load there simply wasn't enough fuel getting to the chamber. The fact that it re-occurred even after dropping gear was because the acceleration drained the float tank in the carb.

Think I'll run it 'round for a while.......