I've got this problem that I can't find the cause of. When starting the engine, which goes very easily, it idles smoothly and stable, rising the rpm a bit still gives no problems. But when driving at high rpm speeds eg. on the highway, and i declutch rpm falls back to 300-400rpm. It's raised again to idle after a second or four. Sometimes i have to rev it up myself or it'll stall. There's no loss in power, pinging or whatever. I've checked the following:
- Air leaks, there seem to be none.
- Mixture, it's set to around 4% CO or lambda 0.93 which is fine for this car ('76 Triumph TR7, SU carbs)
- Ignition advance
- Carbs are synced and the dampers go up and down fine
- Just put new Duckhams Q 20W50 in it
- Drove with and without my PCV system connected to the carbs
The engine has been revised 6 months ago so everything is still clean and in good condition.(ie. nothing clogged or coked or whatever) I've got a Facet performance fuel pump, and the fuelsystem also works fine. It's equipped with stock needles and jets. As far as I know, i've checked everything. A friend of mine told me that although you can't see that, one or both dampers may not go down smooth enough as they should, causing this problem. I doubt that though. As a side note: after the revisation it has as somewhat higher compression, it tends to run on a bit after shutdown. I don't suppose this has something to do with the problem. Suggestions or ideas anyone? Anything is much appreciated. Cheers.