IDLE AND BOOST PROBLEMS

[retrowagen1234]

Hi im new to owning a g40.  been into polos for years tho      so hi im Dan       just bought a 91  dutch import g40  1 owner from new full vw service. 88,000 km .    its developed a bit of a lumpy idle and occasional stalling.   and occasionally it doesnt pull very hard.   say acceleration in second and it will pull hard then go lightly jumpy like its missing    but not that extreme.  its a very soft jump allmost like the feeling of wheel hop but i can feel there is less power.   im wondering along the lines of fuel supply?   i.e filter?  any ideas guys?   

[PeteG40]

sounds like an ignition problem - the spark is strong enough for idle but perhaps not under boost.  are plugs, leads, coil, rotor arm, distributer cap quite new?

[G-spot]

I'll second Pete on the plugs/ignition, also check the lamba sensor too, sometimes they can get contaminated with oil and stop working effectively.
When I did some of the engine mods on mine I found that the spark which worked fine in normal tune was causing a miss fire under greater load. So I tweaking the plug gap in a thou' at a time it soon cleared.

[retrowagen1234]

ok,   its got full vw service history ,  but looking at the condition of some parts under there it dont look like the caps been changed in a while .  and possibly original leads.   im gunna get the charger rebuilt.   any idea how much it costs ?  in regards to different states of tune?  also gonna fully service it and get the cambelt changed as they lost the reciept for that so not sure on last change.  better to be safe than sorry   

[retrowagen1234]

just relised that sometimes it gets to about 4000rpm and falls flat on its face.  like no boost.   but then wont go any further.         it will boost strong up until then and then nothing   

[G-spot]

sounds like your boost leak in the other thread.

[retrowagen1234]

woo hoo   just set the co2 pot too 560ohms  and shes sweet as