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Marty, European Car Expert
Category: UK Car
Satisfied Customers: 53979
Experience:  ASE & Bosch Certified Master Tech. Over 30 years experience.
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Paul I have a 97 230 komp r170 when pushing the car at

Customer Question

Hi Paul
I have a 97 230 komp r170 when pushing the car at higher speeds it will go in to some kind of de acceleration not allowing to say kick down-if you continue to try to push it will start to feel as if its running on three [lumpy] nurse it to a stop -turn it back on and back to normal- it has a coolant light up we have narrowed it down to a new aux relay fan box needed - could this have anything to do with it also?
Submitted: 2 years ago.
Category: UK Car
Expert:  Marty replied 2 years ago.
Hi, welcome to Just Answer. My name is***** sounds like a fuel starvation problem. If the fuel filter has not been replaced I would do that first. My next thoughts would be a weak fuel pump or possibly a fault with the mass air flow sensor. A faulty mass air flow sensor would normally cause the check engine light to come on and store fuel mixture codes in the computer. A faulty pump or filter would not necessarily cause fault codes to be stored. I'd suggest a complete diagnostic scan with the Mercedes Star Diagnosis tester to see if there are any relevant fault codes stored. If all is good I'd try a new fuel filter and then have the fuel pressure tested to check for a weak fuel pump. The aux fan problem should not have any affect on the engine running.
Let me know if you have any questions.