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Discussion Starter #1
Hi, i dont own a benz this question is about my moms car so i dont have as much info as i normally would if it were mine. but.......2003 C320 hesitates badly under 3/4 to full throttle. there is no check engine light on. i dont have service history but aside from normal tuneup stuff is there anything obvious that could be pointed out? i cleaned the MAF and air filters and it helped a little but still major hesitation here. thanks for the help in advance
 

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i'd try changing the fuel filter because it is cheap. you can also try to scan the codes even if the light isn't on because there may be stored codes.
 

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Discussion Starter #3
i thought about that as a possibility, not sure if it has been done yet but when i say hesitates i mean it feels like the ecu is pulling the timing back or a major vacuum leak, light throttle you dont notice it but anything more than half it gets bad
 

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clogged fuel injectors or weak fuel pump are other possibilities. I'd think vac leak would turn on MIL but maybe not. you can try to run a bottle of techron through it. there are places you can send them to (witchhunter.com is one I've used for another car) and they can professionally test and clean them.
 

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CURRENT: 2011 SL550, 2011 C300 FORMER: ML350, CLK550 Cabriolet, C240, ML320, 300TD
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How many miles are on the clock? Anything over 100K and you may be looking at problems with the supercharger or clogged catalytic converters.
 

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CURRENT: 2011 SL550, 2011 C300 FORMER: ML350, CLK550 Cabriolet, C240, ML320, 300TD
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Oops, sorry - I must be getting dyslexic (getting old is a real PITA). I see - C320, not C230. And 81K is probably too early for cat problems, but it's still possible. So, the hesitation, is it only from take-off, or anytime you accelerate, even at highway speeds?
 

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Lol, it happens at any speed, from a start or normal road speeds just runs like $ hit under sporting acceleration
 

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2003 MB C320 4MATIC Wagon
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paranoia?

I just got a C320 4matic two weeks ago. It was a great deal from a legit dealer, but i feel possible hints of the same thing happening to me (or im just paranoid because i DONT want anything to happen)... mine seems to only happen under light acceleration at low speeds. normally when i startup in the a.m.
 

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Well, maybe I fixed it, took it on the highway and kick the $hit out of it, runs good now!
My mom puts 89 octane in too which maybe contributing to the problem
 

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CURRENT: 2011 SL550, 2011 C300 FORMER: ML350, CLK550 Cabriolet, C240, ML320, 300TD
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You know, this thread reminded me of another possibility. - the defective Valeo radiator that lets coolant and transmission fluid mix. Do a visual inspection (see this thread) and make sure you don't have that one.
 
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