cold start rough idle
08-02-2012, 03:29 AM
#1
Member
Thread Starter
cold start rough idle
I did a search for this and I am coming up with several possible issues but nothing really fitting. Here is the deal.
Saturday changed the oil, since then I have put roughly 400 miles on her. I had to drive 4 hours sunday to come to work and she ran like a dream Sunday, monday and tuesday. Go out to her this afternoon to go to work and start her up and she starts up, idles up high and drops to 1k rpm. Does that for a few seconds and I turn the a/c on and after a few seconds I feel a really rough idle, almost like a dead cylinder. Shut the a/c off and its still there, so i easily press the gas and it smooths out. Let her warm up and drive to work without issue. I did an ECU reset before walking into work.
Come out after work and start her up ( ac was left on lowest setting when I shut the car off) right off the bat rough idle, turn the ac off and give her some gas and no response, she cut out for a second and then slightly revved up. Let her idle back down and tuned the car off. Restarted her and the CEL comes on now, rough idle still present, press the gas again and she hesitates and cuts out a little and revs up. I hold her at about 1500 rpm for a few seconds and let off. Rough idle is gone but if I slap the gas I have hesitation. Once she is warmed up I can hit the gas and she responds great. Took her on the interstate and didnt have nay hesitation of stumbling at all. Once home i turned her off and reset the ecu again. waited about 5 minutes started her up, no rough idle but the CEL is on still. I am planning on calling the dealership tomorrow to see if I can get her looked at cause I have to go out of town to Atlanta Friday and i need my car.
Anybody have some ideas or had this issue before I take her to the dealership and find out its something small and stupid. Im at the mercy of the dealership for repairs right now cause im in an apt and looking for a house, so my tools arent here. Just trying to avoid getting shafted by them.
Thanks guys.
Saturday changed the oil, since then I have put roughly 400 miles on her. I had to drive 4 hours sunday to come to work and she ran like a dream Sunday, monday and tuesday. Go out to her this afternoon to go to work and start her up and she starts up, idles up high and drops to 1k rpm. Does that for a few seconds and I turn the a/c on and after a few seconds I feel a really rough idle, almost like a dead cylinder. Shut the a/c off and its still there, so i easily press the gas and it smooths out. Let her warm up and drive to work without issue. I did an ECU reset before walking into work.
Come out after work and start her up ( ac was left on lowest setting when I shut the car off) right off the bat rough idle, turn the ac off and give her some gas and no response, she cut out for a second and then slightly revved up. Let her idle back down and tuned the car off. Restarted her and the CEL comes on now, rough idle still present, press the gas again and she hesitates and cuts out a little and revs up. I hold her at about 1500 rpm for a few seconds and let off. Rough idle is gone but if I slap the gas I have hesitation. Once she is warmed up I can hit the gas and she responds great. Took her on the interstate and didnt have nay hesitation of stumbling at all. Once home i turned her off and reset the ecu again. waited about 5 minutes started her up, no rough idle but the CEL is on still. I am planning on calling the dealership tomorrow to see if I can get her looked at cause I have to go out of town to Atlanta Friday and i need my car.
Anybody have some ideas or had this issue before I take her to the dealership and find out its something small and stupid. Im at the mercy of the dealership for repairs right now cause im in an apt and looking for a house, so my tools arent here. Just trying to avoid getting shafted by them.
Thanks guys.
08-02-2012, 03:42 AM
#2
Member
Thread Starter
its been about 45 minutes after I shut her off and reset the ECU. Just started her up, started up and idled fine and no CEL. 
This is a new one on me for sure.
This is a new one on me for sure.
08-02-2012, 05:26 AM
#3
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C63 507 AMG DA Car #19
Put a code scanner on to see what's what.
Scanner Options:
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Complex - STAR DAS laptop/software/multiplexer from china - $500 (very helpful)
GL.
Scanner Options:
Simple - $50 autozone special
Complex - STAR DAS laptop/software/multiplexer from china - $500 (very helpful)
GL.
