lacelane

I just changed it. I just used generic ones I got on Amazon. It seemed good at the first drive. I was looking at the RPM gauge, it looked like it wanted to shake and jump the gun at a stop, but didn't. If you look closely at the rpm gauge, it went up oh so slightly, you had to concentrate hard to see it. Drove around 4 miles, some at 60 mph. Came back home, it was rough in front of my house, it really wanted to jump forward on Drive. It normally would want to jump and run rough on Reverse, so I tested it out, put on reverse, and it didn't! I was like wow. Much better, but at the same time disappointing because it was running really rough at the end of my first drive. Went on a second drive about 15 minutes later, drove around 30 miles, even stopped to get some gas. This time, very few times it went rough. You had to concentrate and feel the engine through your butt while you are sitting just to see. It did run rough just a little bit, but very short amount of time.

Question is, would changing the coils and spark plugs make it smooth immediately and you shouldn't have that problem anymore? Why was it running a little bit rough right after a change? Is that normal? Haven't driven a third time yet, so I am crossing my fingers here.

Russell Ormerod

Coils don't cause rough idles they cause misfires. You need to keep looking for your problem.
also it would be good to state what you working on!

lacelane

I have a 2005 c230 kompressor sport silver. There were definetely misfires earlier. Didn't pull out my obd2 yet, just driving to see if it was as bad as before, it's not. Some of the problems as I am driving is that when I put the car in drive, it moves very slowly, like it has a hard time moving without gas. I also have a 2004 white kompressor sport, much much zippier and responsive. My 2005 with 255k miles, whenever i push the gas, it's almost like it wants to drive as fast as possible, like it wants to fly. RPMs can go really high. I hope my transmission is not slipping.

lacelane

Right now the problem is that when I put the car in Drive, without me pushing the gas pedal, it would go maybe 10-15 mph. Right now, it barely gets to 7 mph without my foot on the pedal. Is this something wrong with the transmission? Or maybe it's running lean? I had a p0171 code. Someone did mention pigtails, camshaft, something of that sort.

Russell Ormerod

strange tests you are doing! First question, when its in drive is it running on all 4 cylinders?

lacelane

Sorry, I mean normally a car would go 10-15 mph without pushing the gas. I have a 2004 c230 kompressor that runs fine, it's doing it. This one, the 2005, it's slow as hell on drive. I'll look if all cylinders are firing.

slammer111

P0171 is Cylinder 1 misfire. I assume the CEL is on then?

Does the car run rough below 3000 RPM? If one of the cylinders isn't sparking (coils would be the first place I'd look) then you would know. When one crapped out I could barely keep the car moving.

Another easy check - swap 2 coils (cylinder 1 with another cylinder of your choice) and see if the engine code moves with it.

lacelane

Isn't the p301 mean that cylinder 1 is misfiring? I think the p0171 means that the system is running lean or some sort. Could be a vacuum leak. I seriously hope it's not my transmission slipping. I just resetted the check engine light today before my first drive. the CEL didn't come on yet, should be there on the second drive, i'll check then. There were some instances where when i push the gas, the rpm goes up like 3000 more rpm and the speed wasn't changing, this got me thinking, hopefully it's not transmission slipping. And yes, the rough idle is when the car is in low rpm, when it's stopped actually but the car is still on drive. Yesterday there was few rough idles after i changed the spark plugs and coils. Today not so good. I mean, wth right? Today, the mpg went down again, to like 15.5 to 16 in the city.

lacelane

Ok, I just got the check engine light on my second drive, there's no misfire. But I think the second or third drive will get the misfire, just my experience from the last month or so. Even though I just changed spark plugs and coils. Here are the codes:

============1==============
P201C
Raw code: 201C
ECU: 01
Status: Test has not been completed, Validated and stored in non volatile memory
OBDII: Intake manifold air control actuator, bank 2 - supply voltage low
============2==============
P2004
Raw code: 2004
ECU: 01
Status: Test has not been completed, Validated and stored in non volatile memory
OBDII: Intake manifold air control actuator, bank 1 - actuator stuck open
Mercedes-Benz: Particulate Trap Efficiency Below Threshold (Bank 2)
============3==============
P2029
Raw code: 2029
ECU: 01
Status: Test is inhibited by other DTC, Validated and stored in non volatile memory, Validated fault present at time of request, Validated fault has been present during this drive cycle
OBDII: Auxiliary heater (fuel fired) - system disabled
============4==============
P0128
Raw code: 0128
ECU: 01
Status: Pending
OBDII: Coolant thermostat - coolant temperature below thermostat regulating temperature
============5==============
P0171
Raw code: 0171
ECU: 01
Status: Pending
OBDII: System too lean, bank 1
============6==============
P0171
Raw code: 0171
ECU: 01
Status: Confirmed
OBDII: System too lean, bank 1