noisy engine on acceleration
1994 Euro C180 194,000kms.
When I accelerate there seems to be a bit too much of this difficult to describe chattering or mechanical sound coming from the side(right side driver's window) . It seems like it is the fuel injection sound or the engine firing away, but it doesn't seem to be so obvious in other cars like my Camry 2001 model. This one brrurs along even on hard acceleration, a less objectionable sound than the hard swishing sounds? Someone told me that the alloy piping from the engine to the injector makes this noise and on later models were changed to the black plastic looking ones which don't make this noise. Mine are extremely clean looking like brand new with almost chrome looking rough textured surface like from a sand mould, is this OEM? This doesn't seem to affect the performance at all, it idles a bit high near 900 most of the time, could be too high. Maybe its actually 850, don't know. What should it be? Will ask my indie to run a test again, last time he said everything was ok 2 months ago. This noise was there since I got the car in May 1992 and its not pinging or detonation. It appears to be worse when going through tunnels with all the enclosed walls. Petrol and oil usage is normal, the car is very economical to run with only 1799cc. I am a very non-tech person, so please give me some idea in plain language, many thanks to anyone who can throw some light on this matter. Is it just normal for a Benz 4 banger?