'85 380SL Tune up
I bought my 1985 380SL 2 years ago and started working on it. I's in really good shape and starts well. I decided to start replacing engine tune up parts because it was idling rough. I changed the plugs, rotor and cap. I have not yet replaced the wires or fuel filter and have not re-timed it. I did adjust the idel speed from that hole on top of the air cleaner.
My problem is this. The car starts fine and seems to idle pretty smooth for a while. Once warmed up, I can hear what sounds like some missing. There are puffing sounds at the tailpipe, but no smoke. I took the car on a long 60mph run today. At high speed it runs smooth but idles a little rough once I stop. I feel flat spots on acceleration at a standstill and if I accelerate under load at high speeds (eg uphill), the engine doesn't have the pick up it should.
I am planning to replace the wires and fuel filter soon, but I wonder of it could be some other problem, like fuel injectors or fuel pump. I hate to take it to Mercedes at this point, because it seems like it may be a minor problem. Should I check the timing? It's not backfiring. Also, is there a diagnostic plug in the engine compartment that Mercedes can hook up to and maybe diagnose a problem? Any help or suggestions are appreciated.