Hi guys

Need some help with my Euro 2.5 16 - Problems are as follows;

1. Rough idle - I have replaced Idle control servo/unit, cleaned the Idle control valve, replaced spark plugs, 4 x injection nozzles , vacuum pipes, fuel filter, no inlet manifold leak, replaced engine mountings, air filter assembly replaced, Air intake temperature sensor, Optimax fuel with octane booster.

2. Gearbox rattle which goes once clutch is depressed. Dog leg first and reverse gear very difficult to engage.

3. Rear axle whine which goes once speed exceeds 80 mph

4. SLS has been replaced with Europarts Shock absorbers/rubber blocks and OEM springs - the rear of the car is very bouncy so need some advice on whether this combination is flawed.

5. Oil pressue gauge is very bouncy once the engine is hot - appears to be sticking.

I am thinking of replacing the spark plugs with Denso Iridium plugs, what part number would be best for my car and is this likely to remedy the problem. If this does not work I am looking to replace the throttle switch but mercedes are quoting £350 as the switch comes with the complete throttle body.

I hope you can help as this car is a fantastic car to drive but the drive train seems to be struggling to cope with 205bhp(non cat)