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.

The engine wiring harnesses are bad on all engines from 1993-1995, and they seem to demonstrate problems particularly on M104 engines, like yours.

The insulation on the wires goes bad, and flakes off all along the wiring. You can look at the wiring harness where it connects to the injectors for proof.

There have been several pictures posted on this site of flaking wiring insulation. Just do a search on "wiring harness" and you should be able to find these posts, should you have enough patience.

The wiring harness can be purchased through this site on Parts Shop / Fastlane for less than $500, I believe.

However, before I'd replace the wiring harness, I'd definitely replace your three coil boots. They are the most common cause of misfires on M104 engines.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".