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.

 

Do you have a cold air intake on there without a sheild? Because AC fan blows onto the air element and makes it fluctuate. If you don't, it's probably a vacuum leak where the line from the fuel pressure regulator goes to the intake manifold

 

I hope you figure it out man :/ I'm sure you'll find your answer here though GL

 

 

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

 

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.

 

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

 

I have a similar issue. You more than likely need a tune

 

My 08 does it once in a while too. It seems to be a pretty common thing with a lot 10's. After it was tuned, it helped a little it happened less frequently.

 

oh, you have an injector cutting out then, when it's spiking to 18 that means it's stuttering.

it should already have a tune, but even then it shouldn't be doing this

please tell me you guys all have the updated fuel pump relays

 

im guessing the maf sensor

this happened to me twice, once with the almighty hose on the IM and when my MAF sensor went

 

at 12k tho? I guess mine went at 55k

 

Mine went at 14.5k, yes I was shocked too

 

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)

 

Just came back from the dealership they said they flashed something per TSB-12-13-002 and from the short drive to my house it looks like that fixed it.