Weird RPM fluctuation
#1
Newbie
Thread Starter
Weird RPM fluctuation
Hi,
I have had this for some time now on my car and it's starting to bug me. The car drives fine but when I put the clutch pedal down the RPM will fluctuate (a lot, not like the other issues I've seen).
It mostly happens if I have the AC on, but sometimes it will do it even without.
Here's a video: http://tinypic.com/player.php?v=24lpt9u&s=6
If I have AC on it sometimes does it indefinitely like in the video (where I just put the clutch pedal down while driving at a steady 50kph to see if it would do it). But this also happens when coming to a red light for example where it will fluctuate for a couple seconds then go back to a stable idle.
I have had this for some time now on my car and it's starting to bug me. The car drives fine but when I put the clutch pedal down the RPM will fluctuate (a lot, not like the other issues I've seen).
It mostly happens if I have the AC on, but sometimes it will do it even without.
Here's a video: http://tinypic.com/player.php?v=24lpt9u&s=6
If I have AC on it sometimes does it indefinitely like in the video (where I just put the clutch pedal down while driving at a steady 50kph to see if it would do it). But this also happens when coming to a red light for example where it will fluctuate for a couple seconds then go back to a stable idle.
#2
Evolved Member
iTrader: (18)
Hi,
I have had this for some time now on my car and it's starting to bug me. The car drives fine but when I put the clutch pedal down the RPM will fluctuate (a lot, not like the other issues I've seen).
It mostly happens if I have the AC on, but sometimes it will do it even without.
Here's a video: http://tinypic.com/player.php?v=24lpt9u&s=6
If I have AC on it sometimes does it indefinitely like in the video (where I just put the clutch pedal down while driving at a steady 50kph to see if it would do it). But this also happens when coming to a red light for example where it will fluctuate for a couple seconds then go back to a stable idle.
I have had this for some time now on my car and it's starting to bug me. The car drives fine but when I put the clutch pedal down the RPM will fluctuate (a lot, not like the other issues I've seen).
It mostly happens if I have the AC on, but sometimes it will do it even without.
Here's a video: http://tinypic.com/player.php?v=24lpt9u&s=6
If I have AC on it sometimes does it indefinitely like in the video (where I just put the clutch pedal down while driving at a steady 50kph to see if it would do it). But this also happens when coming to a red light for example where it will fluctuate for a couple seconds then go back to a stable idle.
#5
Newbie
Thread Starter
I have the oem airbox with stock filter.
I zip tied the fpr hose as soon as I got the car too so it's ok.
I have a boost gauge and checked the hoses and they look fine too.
hope it's nothing serious
I zip tied the fpr hose as soon as I got the car too so it's ok.
I have a boost gauge and checked the hoses and they look fine too.
hope it's nothing serious
#6
Evolved Member
iTrader: (18)
Does the boost gauge show a fluctuation with the idle? Are you running a stock blow off valve? If the BOV was leaking it could let in unmetered air. How many miles?
Also check your fuel pump relay is the new one, check your plugs, fuel filter, fuel pressure and plug wires.
#7
Newbie
Thread Starter
well, just looking might not help. You need to check for leaks. you can do this the old school way by spraying the vacuum lines with carb cleaner or starting fluid while it's running. If the engine suddenly revs, there's the leak.
Does the boost gauge show a fluctuation with the idle? Are you running a stock blow off valve? If the BOV was leaking it could let in unmetered air. How many miles?
Also check your fuel pump relay is the new one, check your plugs, fuel filter, fuel pressure and plug wires.
Does the boost gauge show a fluctuation with the idle? Are you running a stock blow off valve? If the BOV was leaking it could let in unmetered air. How many miles?
Also check your fuel pump relay is the new one, check your plugs, fuel filter, fuel pressure and plug wires.
And no fluctuation on the boost gauge. It move like 1 psi when the problem happens but normally it doesn't fluctuate at all.
Got 12 000 miles.
The weird thing is it seems to do it only when moving. If I press the clutch in and come to a complete stop it will stop fluctuating, but if I just press the clutch in at speed that's where the problem occurs...
Edit: my AFR gauge goes crazy though, goes from like 13.5 to 18 at each of the little revs you see on the video
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#10
Evolved Member
iTrader: (18)
I see I see. I'll look into all of this. But yeah the car is stock apart from a perrin catback + mil.spec cat. (the car did this before the exhaust change though).
And no fluctuation on the boost gauge. It move like 1 psi when the problem happens but normally it doesn't fluctuate at all.
Got 12 000 miles.
The weird thing is it seems to do it only when moving. If I press the clutch in and come to a complete stop it will stop fluctuating, but if I just press the clutch in at speed that's where the problem occurs...
Edit: my AFR gauge goes crazy though, goes from like 13.5 to 18 at each of the little revs you see on the video
And no fluctuation on the boost gauge. It move like 1 psi when the problem happens but normally it doesn't fluctuate at all.
Got 12 000 miles.
The weird thing is it seems to do it only when moving. If I press the clutch in and come to a complete stop it will stop fluctuating, but if I just press the clutch in at speed that's where the problem occurs...
Edit: my AFR gauge goes crazy though, goes from like 13.5 to 18 at each of the little revs you see on the video
it should already have a tune, but even then it shouldn't be doing this
#14
Newbie
Thread Starter
I'm taking it to my dealership tomorrow so we'll see what they say.
I tried the vacuum leak test with carb cleaner and there wasn't any change in the idle.
It seems to have something to do with airflow since it only does it when the car is moving and the outside air is hot. It started doing this at the end of the summer but when autumn came the issue disappeared so I forgot about it.
Now in the mornings it won't do it since it's colder outside but near noon it comes back.
And I should have the newer fuel relays...my dealership changed them twice (from first black to blue ones to newer black ones)
I tried the vacuum leak test with carb cleaner and there wasn't any change in the idle.
It seems to have something to do with airflow since it only does it when the car is moving and the outside air is hot. It started doing this at the end of the summer but when autumn came the issue disappeared so I forgot about it.
Now in the mornings it won't do it since it's colder outside but near noon it comes back.
And I should have the newer fuel relays...my dealership changed them twice (from first black to blue ones to newer black ones)