Been lately plagued by an intermittent problem.

The rev counter sometimes goes crazy and read different values from what it should. Sometimes, even though the engine is idling at it's 750'ish rpm, the needle on the rev counter reads, sometimes 1500 or other times as low as 300. Then all the way through the rev range, that ''gap'' is maintained. So sometimes, even though the engine is reving at 1500 at cruise, on the binnacle i'm getting 2000 or the other way round 1000...

When it is under ''the problem'', when i shut the car down, the needle instead of dropping to below 0, drops to a position based on the interval to what was idling at, meaning it drops to a value of 700 if the value was 1500 idling.
After a few hours, when i return to the car, everything is back to normal.

What can be the problem?