Hi guys, about two months ago a new problem developed. The car runs very rough, almost like a student driver having the first driving lesson in a manual car, it most certainly does not fire on all cylinders, it crackles, vibrates and gives the occasional bang from the exhaust. But the weird thing is that all of a sudden - everything is fine, especially if it has been driven at speed for some time. When it runs great, it's better than ever. That would lead to think that it's related to the cold start valve, but it cannot be, as the rough running returns intermittently - also with a warm engine. Since the problem occurred, I've changed the distributor leads, coil, plugs and have had the valves, timing etc. set at a very renowned engine tuner (famous for building classic racing engines). But all to no avail :-(
So my question is - can this be related to fouling of the fuel system? And if yes, what is the easiest way of troubleshooting this? Where are the fuel filters located?
Thanks in advance
Ulf