misfire sometimes

[Laurence Clarke]

My C280 1995 vintage has been misfireing on and of for two weeks. Sometimes for two days it runs perfectly,then the third day it misfires,if the engine is shut off and restarted immediately it runs perfectly again.
I have replaced the gas filter which was maybe 75% blocked. The fuel pressure is steady at 52 psi including when misfireing.
When the misfire starts it is always cylinders # 1 2 and 6. Are those the cylinders that the fuel is cut to,to prevent overreving?
The lack of technical manuals available to the public is a disgracefull practice by MB NA.
I have found that the engine wire harness deterioates on these cars and cause a misfire. Is there a specific location on the harness that is problematic?
I am thinking that my problem is a bad airflow meter but there has been no malfunction light turned on.
If someone have had this problem before please reply,i am hopeing it is something other than the wire harness,$1100.00 is a little too much for wires.