Mk 3 150 bhp 96 abf. Misfire problem and rough idle

[jaypb]

Please forgive me as im new and not the most mechanically minded.
I see from reading the post this seems to be a common problem. It is itermitant problem but when it does occur its when i hit 3000 rpm she will start to jerk in every gear.  at at idle it dips back and fore between 1000 and 800 rpm, not stall though .some times it will run for weeks fine then all the sudden the problem returns
have changed all the basics
coil pack
cambelt
fuel filter
plugs
dizzy
rota arm
lombanda senser
fuel relay
ht leads
Not sure what to try next, had her on diagnostic machine last week and no faults reported, he also checked all lead and coil to make sure all ok and not arcing.Any help would be greatly appreciated

[justalex81]

give the throttle body and the idle stabilisation valve a good clean. Check all breather pipes for blockages

[rocketron]

i have the same problem with my 16v. a friend of mine said his mate had the same problem and it turned out to be and intermitent problem with the ecu giving irratic voltages. had it reprogrammed and that cured it. hope that helps

[DazVR6]

Try changing the ecu relay, number 30 or 167, i always get mixed up . make sure you get this from the stealers. Also change your vacuum lines, swap em for some 3mm ID stuff (doesn't collapse when hot) especially the one between the inlet manifold and the ecu.

As also said give the throttle body a good clean with some carb cleaner and also the ISV.