Got a problem with my Mk2 Gti (8 valve). Everynow and then, and especially when the engine is hot, it will kangaroo. It sometimes happens when I floor it to overtake and the kangarooing/juddering seems to subside if I ease off the accelerator. I've checked the plugs, leads, and distributor and they seem fine. Also checked air intake hoses etc for splits and they seem ok too. I've noticed that the main fuel pump at the rear of the car (drivers side) makes a loud buzzing at idle - you can hear it clearly with the window wound down. Just wondered if this pump is on the way out and is linked to the kangaroo problem? The engine definately runs hot - I don't think the fan is coming on, so I need to sort that asap. Could that also be linked to the kangarooing? I'm grateful for any feedback, because this problem is ruining an otherwise great car! Regards, steffmo
Noisy main pump is usually caused by a failed lift pump in the fuel tank. If the lift pump isn't working then the main pump will be struggling. I imagine this could cause the kangarooing... It's worth testing/replacing the lift pump as it's the cheaper of the two but some damage may have been caused to the main pump already.
there's this guide i used for my lift pump. i added some pics to it and the lift pump part numbers. although they might be different for your car as mine's a kjet 16v http://www.clubgti.com/forum/showthread.php?p=1940627#post1940627
I had similar symptoms, very occasional kangerooing and that turned out to be the ECU relay, number 30
30 is a mk3 relay, it'll still work in a mk2 though. the mk2 relay is #32 but it has been deleted by vw so you need to order the 30 relay instead edit: unless its a pre-90 digi, if so the ecu relay is a #53
Worth taking off your air intake pipe and give it a really good flex, could be split inside the corrugated bits that won't be obvious until you take it off
