car shaking violently

[RichielightweightGT]

i have an odd problem in 3nd 4rd gear if you leave the revs die down to about 1800rpm my car just starts to shake violently really judders like its got kangaroo petrol in it, ive changed my icv and plug leads and cleaned dizzy and rotor, it idles at 1200rpm lowest and usually around 1800 rpm with 2000rpm being the highest, when you rev it at idle it comes down and revs itself up a tiny bit and comes back down again, can seem to figure out whats up with it i reckon its an electrical problem but the timing could cause this? any info would be great :rockon:

 

[AdamB]

Check for any boost leaks, if you have had any pipe work off check that as well. It could also be the idle control valve which you can take off and give it a
good clean.

 

[garry goodall]

as said above sounds like you icv valve, did you fit a new one or a second hand one when you replaced it?, i think when it drops down to 1800rpm it starts to try and idle which could be the reason for the jerking?
keep us informed

 

[weeJohn]

Tps

 

[RichielightweightGT]

i have changed the idle control valve for a one off my spare engine but the car that that was in always idled perfect and mine was full of oil because it was twice the weight of the new one and it used to idle way way higher before i changed the icv, when you rev the car wile the revs are dropping down when it gets to 1800 its like some sort of sensor stopping it from idleing down at 950 its really gettin on my nerves if its the tps would a second hand one be knackered? i tried the idle screw and it just started hunting mad unless the screw is nearly all the way clockwise

 

[RichielightweightGT]

any1 got any ideas for me?

 

[RichielightweightGT]

bump