GTI 8v MISFIRE WHEN COLD

[GTIMKiiJODE]

My mk2 has got a bad misfire when engine cold. Clears within 2 mins of starting. Put new dizzy cap leads and plugs on. Sorted problem out for two weeks and now it has started again. Any ideas would be much appreciated

[golfvr6]

If its a k-jet then maybe a worn worm up regulator.

[GTIMKiiJODE]

Dignifant 2 not K-jet. thanks anyway

[golfvr6]

try changing the coolant temp sender.

[GTIMKiiJODE]

Don't think that will help much. Think it is more electrical ignition fault. The engine is warming up fine, just misfiring when engine is cold in mornings.

[mk1]

Are you sure that the missfire is electrical, as vr6 said it could be a fueling problem. Unusual to replace the dist cap, ht leads and the plugs and not the rotor arm, try a new rotor on as the worn rotor will have worn giving you a big air gap.

[GTIMKiiJODE]

Changed rotar arm aswell. VR6 maybe right. Probably not electrical fault. I am not brilliant with engines. Going to check coolant temp sender - the one that talks to the ecu right. Fingers crossed.

[Veedubgt18v]

try changing the coolant temp sender.

this is well worth checking, if its wrong you can idle bad and generally run crud, they arent expensive so prob worth changing anyway!

[GTIMKiiJODE]

Changed coolent temp sender, made no difference. Took it in to VW garage, they reckon it is the fuel pressure regulater. Apparently fuel pressure should be around 4bar but they tell me mine is running at 7 bar which is far to high, Hence to much fuel being pumped in so engine struggling when really cold. Ordered pressure regulator - ?55 squid. Hope they are right.  

[GTIMKiiJODE]

Yeap they were right - fuel pressure regulator. Running really well again. love it