This vehicle will not run over 4500 rpm. It starts normally, and idles okay. Dealer says it needs D1 and D2 EZL ignition units plus Rt and Lft electronic throttle actuators. Dealer advises must replace throttle accuators in pairs. Independent MB mechanic advises EZL units are good, but feels fault is in right electronic throttle actuator. Two fault codes were stored, one was 4830. Vehicle has new plugs, rotors and caps, and fuel filter. Vehicle has ASR traction system. When reaching 4000 rpm, engine soulds like it can't get enough air. Any ideas???

 

Check your cats first,I had lack of power over 4000rpm,replaced them and car screams again

 

How did you make out? I have at least one bad Throt Act. I have parked my SL until I can find a lower cost solution