strange IDLING.... How can i solve?

[lensflare]

Hi guys,

i have noticed that my 2000 BUSA (20'000 KM) have a strange idling.... i try to explain you:

when i start the engine, the idling is not perfectly
pointed, and it flows of a little 100-200 rpm more or less, but this is no real problem.

the annoying fact starts when i drive the BUSA for a while, expecially if i drive it hard, and so, when i stop it to the neutral (for example at a lightstop in the city), the idling becomes VERY instable, flowing +/- 500 RPM, so it sounds like someone is tricking with the gas...

do you think that a clogged fuel filter can cause it? or should i attempt to synch the injection bodies?

at high RPM the engine has no problems and it revs as hell

 

[Don Hardcastle]

What RPM is the idle set at? Mine idles at 1150 nice and smooth. If if gets down to 900 - 1000 it idles very rough. If the throttle bodies have never been sync'd that needs to happen.

Don

 

[MC MUSTANG]

+1 On what USN said - check your idle when warm and see where it is, I'd bet it is at 1K or less - it is a very simple adjustment on the right side, under the tank.

 

[lensflare]

thank you boys,

quote you for the synch needing..... synchronization of throttle bodies has never been made...

i have set the idling to 1100-1200 rpm at warm, and i have checked that
when warm it idles from 1000 to 1500 with very wide range.... ti seems that i'm turning up and down the GAS command ve quickly...

this happens more deeply when stopping from a ride.... insert the neutral, stop and..... HERE it begins to go up and down very strangely.

i hope it to depend from the throttle synch, andi'm going to synch them....

but, if someone of you shold know any oher cause, or checking to do, please give me any suggestion...

thank you in advance brothers!!!

 

[Powers739]

I'm thinking of a vacuum leak, if that's possible, check hose connections... May not apply to the busa I will have to look at the manual...

 

[Burger King]

+1 on the sync and definitely check for cracked vacuum lines while you are around the throttle bodies. I haven't had any problems with the stock vacuum lines but some of the aftermarket vacuum plugs I've bought from auto parts places have been less than satisfactory.

 

[ABP]

When is the last time you replaced the spark plugs. My Friend bought an 03 with 9500miles. It ran rough at idle. I read on here to replace the spark plugs every 7500miles. We put in new plugs and his is smooth as silk.

 

[lensflare]

Right guys,

so:

1) check and eventually replace spark plugs
2) check and eventually replace vacuum lines
3) do a GOOD synch job

so.... it would be fine...

so, just the time to have these works done and i will post my impressions...

thank you for now