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Juddering whilst driving/losing power?

Posted: Mon Oct 06, 2014 11:20 pm
by LeonDixon
Hi all, recently acquired a 90' spec GTII. The first few days driving it was running good, no problems. Now i've come across a juddering, losing power in all gears. I can drive for a mile or 2 and it's fine, it then decides to start juddering, losing power, I take it out of gear into neutral and it just dies on me. After a few minutes it starts up and a mile or 2 down the road and i've got the same problem.

Anyone able to shed some light on this??
Thanks in advance.

Re: Juddering whilst driving/losing power?

Posted: Mon Oct 06, 2014 11:32 pm
by ianaudia4
Sounds like a fueling issue. Is the in-line fuel filter full of crap? If the filter is full of crap it will need changing. What carb have you got fitted, standard or a Weber, does it still have a swirl pot?
Is the filler neck rusty, common problem?

Re: Juddering whilst driving/losing power?

Posted: Mon Oct 06, 2014 11:40 pm
by LeonDixon
I'll have a look tomorrow after work as I need to change the rocker cover gasket on it as well. It's just a standard carb. The filler neck looked fairly solid to me.. but will also check this out tomorrow in a bit more detail. Anything else i should look for?

Re: Juddering whilst driving/losing power?

Posted: Tue Oct 07, 2014 8:59 am
by ianaudia4
Go through the usual checks, carb base fuel lines (ensuring they haven't collapsed), clean air filter, dizzy cap and rotor arm in good order and not forgetting the HT leads.
Are you fitting the uprated rubber rocker gasket, much better than the cork affair?

Re: Juddering whilst driving/losing power?

Posted: Tue Oct 28, 2014 10:47 pm
by scrappy1382
i had a similar issue with my last gt2 ( boy what a headache it was too ) turned out to be the 'flange' which connects carb to inlet ( if that makes any sense ) check that first

Re: Juddering whilst driving/losing power?

Posted: Wed Oct 29, 2014 8:07 am
by the edmundator
The two problems I've had that caused these kind of symptoms are:

1) Rust in the fuel system - you need to look very carefully at the in-line filters for sediment and inside the tank. If the car's been laid up for any length of time or the filler neck and tank haven't ever been replaced, rust is almost a certainty.

2) faulty ignition amplifier. Found on the front scuttle, under the rain tray. Easy to check if this is the problem by substituting a known good replacement.

Re: Juddering whilst driving/losing power?

Posted: Wed Nov 19, 2014 12:47 pm
by filmidget
With those symptoms and the recent change to colder/damper weather it could also be carb icing.

Might be worth checking that the warm air feed to the carb is intact and working, and that the carb and 'hedgehog' manifold heaters are working.