Car revs up and down when not in gear

[kilmo_172cup]

I replaced my air filter and gave the air box a clean the other day on my 2003 172 Cup. However, ever since then the revs keep going up and down between 1250 and 1500rpm when the car is not in gear, such as when I am stationary or if I put it in neutral and roll at any speed. Its also more difficult to get a smooth start when in first gear, instead the car will often judder slightly before getting going.

When this first happened there would also be a slight increase in the revs whenever I dipped the clutch to change gear, but this doesn’t seem to happen any longer, its just the issue with the revs constantly going up and down.

Any ideas what this could be?

 

[DrR]

Have you made sure you plugged in all the little hoses on the 90 degree bend?

 

[kilmo_172cup]

Do you mean the one connected to the pipe that attaches to the throttle body? If so, yes. Are there any others?

 

[DrR]

i think there is 2, one goes to the acoustic valve and the other goes behing the coilpack?

 

[Jonny1*2]

there isn't one attached to the coil pack, but there is one at the back right hand side and front right also. Might be one of these, but you wouldn't have removed them if you were just cleaning the airbox surely????

 

[kilmo_172cup]

I'm pretty sure that I have connected everything correctly back together when refitting, but I will check again. Thing is, why would it have got better by itself after a few days if something is disconnected? Is there anything else that may cause this?

 

[DrR]

there is one that goes behind the coilpack it goes from the 90 degree bend to there.

 

[kilmo_172cup]

I took the whole air box out but I put everything back that I disconnected. Unless something has come out by accident. What do this pipes look like exactly and what do they do so I can make sure they are connected properly?

 

[Jonny1*2]

there is one that goes behind the coilpack it goes from the 90 degree bend to there.

A pipe? or an electical clip? :S don't remember removing one, but might be wrong. Plenums off at the mo as well.

 

[Jonny1*2]

I took the whole air box out but I put everything back that I disconnected. Unless something has come out by accident. What do this pipes look like exactly and what do they do so I can make sure they are connected properly?

Could anything have been knocked? TB electrics? Loose wire?

 

[kilmo_172cup]

I've just checked that pipe that goes behind the coilpack and its connected properly. I took it off and there was some oily gunk in it so I cleaned that out, but as I say it was always connected.

Something may have been knocked, I just don't want to have to buy a new TB unless I'm absolutely sure that this is the cause of the problem given their price. I have checked every plug that I can see today and nothing seemed to be loose.

 

[DrR]

A pipe? or an electical clip? :S don't remember removing one, but might be wrong. Plenums off at the mo as well.

Picture this on the car

That smaller pipe goes behind the coilpack, almost underneath it.

And this one

Circled in black, I think if that ones disconnected at either end it causes high idle.

 

[kilmo_172cup]

My pipe is definitely connected to the point underneath the coilpack. The other pipe that you have circled in black is also connected, but I dont know if the other end of this pipe is connected properly.

Could this also be the cause? And where does the other end go?

 

[Jonny1*2]

Picture this on the car

That smaller pipe goes behind the coilpack, almost underneath it.

And this one

Circled in black, I think if that ones disconnected at either end it causes high idle.

Ah i'm with you now

That doesn't make a difference on mine when removed. The front one will though.