Mk2 strange problem

[Snap]

After driving on the motorway for about an hour the power delivery of my car seems to be stange. If i want to go over 75mph the car starts to vibrate and after a while the shaking continues at lower speeds. Im forced to stop the car. I turn the car off and start it again with in 5 mins.

I set off and i reach 70mph and after 10 mins the same happens again. So i go through the process again and again but it gets frightening when im on A-roads as there is no hard shoulder. Its not an over heating problem as if i take routes with lots of traffic lights and speed of under 50 then there is no problem even though im driving for about 2 hours. So what could it be?

[Justins145bhpMK1]

Could be many things, check for air leaks, clean out the throttle body etc. There are quite a few posts on similar probs, especially with MK3 GTI's. Good luck.

[Mr Blue]

does the car still shake when you come to a stop?

Engine mounts, CV joints cause bad vibration. Are the wheels aligned.

[rubjonny]

Classic carb icing mate, check the warm air feed from the airbox to the shroud round the exhaust manifold is intact, and that the warm air flap opens correctly.

Check the heater on the front of the carb gets 12v when the ignition is on too.

[Veedubgt18v]

Classic carb icing mate, check the warm air feed from the airbox to the shroud round the exhaust manifold is intact, and that the warm air flap opens correctly.

Check the heater on the front of the carb gets 12v when the ignition is on too.

 once you stop and let the ice melt it should be alright once its warmed thru. only used to experience it once on my car then it would all be fine after that
 i would check all you ht leads dizzy etc cos it could be an ignoition problem or an advance problem with the distributor

[rubjonny]

Doesn't matter how warm the carb is, it can happen several times in one journey or not at all.  It depends on the conditions outside and how badly compromised the warm air system on the carb actually is.

I had the same on my Driver, on one journey it would start to missfire & loose power, then seem ok.  It did this twice before actually dieing completely and leaving me on the hard shoulder.  After 5 minutes it was fine and off we went!  During the weeks that folowed it was pot luck whether the car would stall when coming up to junctions or not driving to work & back, untill I eventually managed to fix the metal shroud back on the exhaust manifold.

The fact that it keeps doing it, and is fine if left for a few minutes points at carb icing more than anything else.

[Veedubgt18v]

but for it to happen after an hour of driving is weird. 20 mins yeah in my experience but not an hour! sounds like a misfire to me, either way check both things got to be one of the other
 
but then if its a pierburg carb good luck cos theya re notoriusly sh!te

[rubjonny]

No its not weird to happen after an hour, I would get carb icing problems at motorway speeds after hours of steady crusing.

Like I said it depends on the conditions and what is actually wrong with the carb.

[Veedubgt18v]

and what is actually wrong with the carb.

like being a pierburg??

what if he turns round now and says it kjet or digi? 

[rubjonny]

Then his sig is lying