Ford fiesta 1983, 400.000Km running fine, no oil loss but has lost power?

I would personally try the Slick 50--the If you have access to a compression tester, it would also be a solid idea to take readings before and after.

The tricky thing with engine issues is that (obviously) you never know for sure what the problem is...until it's fixed. And sometimes the answer can come from wa-ay out in left field. In 1968, I had a 1960 Chevy with a 283 V-8 which blew up entirely in the middle of the night (on the highway).

Lost power, engine died, clouds of oil-smoke everywhere. Dead beast.

It turned out the clip that holds the distributor in place had broken in half. The distributer jumped up, went absolutely out of time, and...!

Literally took one penny to fix it. Stuck one edge under the retaining bolt, the other over the distributor edge, cinched it down, and it was good to go. Ran it that way for many more miles before trading it in.

It could also be issues with catylatic convertors, im not sure if your car has one. But issues I've seen with cars between 1995-present is when the catylatic convertor gets clogged up, the engine is not about to breath so all that exhaust runs back into the engin. Have you checked that out?

Thanks, no catalytic converter on Mark I fiesta, I think they came in with Mark III (1992 ish).

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.