Date registered: May 2009
Vehicle: 1997 C230
Location: Far Left Lane
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Hesitates on acceleration
Well i thought i had this solved by changing the spark plugs last fall but it's back and getting worse.
The issue is:
1) a hesitation or stutter when accelerating from a full stop. the harder I accelerate the more it hesitates. but only on take off, as if it cant handle the sudden surge of gas. If i baby the pedal (and i mean really ease on it) from a full stop nothing happens.
2) when stopped at a light the idle is perfectly fine and steady except for these sudden dips in rpm and the engine rumbles/shakes, then back to normal. these dips are very random and don't last more than a second.
3) when in reverse these same dips in rpm and shaky engine get more intense and more constant.
4) sometimes when i'm decelerating to take a turn (down to about 30km/h) and then accelerate again after that turn, upon resuming that acceleration the problem gets really bad.. its very sluggish and it seems like i lose the function of a cylinder and am now running on 3 instead of 4. but here's the kicker.. I can quickly restore that cylinder by restarting the car while driving (by turning the key off then back to ignition quickly) and just like that the car goes from limper to normal, instantly!
I scanned for codes and even though i was sure i was gonna get a cylinder misfire code (which is what came up when this happened last year) there was no code related to this! (the only code that came up was a fuel level sensor; which sometimes shows empty after a fill up)
-I checked the spark plugs which were changed in the fall.. They're good (Bosch F8DC4)
-I checked the wiring and boots.. they're good.
-No visible cracks in the 2 coils..
-Air filter and throttle body are clean.
-I haven't changed the MAF in the 2 years that I've owned the car, and i tried running the car with the MAF unplugged; the problem was the same except now the idle was constantly low and rough.
The problem is slowly getting worse. I'm contemplating ordering a new MAF or maybe a set of new coils.. The fact that I can restore cylinders to normal by doing a quick restart makes it clear to me that this is an electrical problem..
Any help before i start replacing parts that are otherwise fine???