Have Mercedes Questions? Ask a Mechanic for Answers ASAP
Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.
The most common cause for the lack of power and sound you hear under load or when power is needed is a restricted catalytic converter.I have seen the catalytic converters restrict on this model here requiring replacement when they due restrict.If you have not had an exhaust back pressure test done at all to see if this is the cause here this needs done.If found restricted the affected catalytic converter needs replaced.Your exhaust back pressure should not exceed 1.5 psi at any rpm range.If it does then this indicates the catalytic converter being tested is plugged needing replaced.
You can rent an exhaust back pressure tester from a local parts store and thread it into the pre cataltytic converter oxygen sensor port to test this pressure.
If found to be o.k. the other cause is a restricted fuel filter needing replaced or a weak fuel pump that isnt supplying the correct amount of fuel pressure or fuel volume.The fuel system would then need tested to see if a component is found to be at fault needing replaced.
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