Problems reving over 4000rpm - 155V6
I have a strange problem with my 1992 155 V6. It had a massive service done just a month a go (all new clutch set, crankshaft gaskets, cambelt and waterpump with all belts).
Now it doenst rev over 4000rpm. It idles really well, without vibration and revs really nicely until 4000 and then röötötötöö.
Car has been tested with 3 different ignition coils (all had the same problem), new spark plugs have also been installed, new throttle potentiometer (Bosch) too.
There seems to be no air leaks in air intake system and no mechanical damage in throttle cable area or sparkplug leads.
There is some kind of sensor for revs and ignition in the cambelt zone (according to pictures)? Could it be the problem? As i wrote, cambelt change was done, so this could somehow be a result of that.
Or the air mass box could be damaged, or something. Maybe lambda or some fuse or relay? What happens in this engine above 4000 rpm:s?
Really got my head twisted with this one and have no idea of what is going on. Probably a simple problem because car is running really well and has power...until that damn 4000 line.
Please give me some clues what to do next. If someone has had this earlier and could help, i would appreciate it a lot.
With kind regards