VW Golf mk3 engine stutter

[duke thrust]

Hi,

I have a problem with my mk3 Gti 2.0 8 valve: When I'm on the motorway (and pretty much anywhere else when I can get over 50 mph) and I'm on part throttle (not quite on the over-run, not accelerating, just cruising really) the car seems to stutter. All of a sudden for a split second it's as if the engine cuts out and you get a jolt through the car and then it's fine again. It doesn't seem to do it when accelerating or braking and it doesn't do it when cold. The gauges don't die and the stutter is really quick, over in a flash. It doesn't feel like a fuel problem i.e. no loss in power (apart from during the split second), no missing or popping - but obviously I can't be sure.

I've replaced the plugs and coil and fairly recently the water temp sensor, before I spend more cash on the leads, cap and rotor arms does anybody have and ideas as to what could be causing the problem?

All suggestions gratefully received!!

[deltaf]

Check all the earth points on the cylinder head for a start.
If theres no problem there, id be inclined to say its running a little lean, however, im not certain of that.
Might be worth having a look at all the vacuum hoses for splits etc too.

[edc]

There are known problems with the crank speed sensor and coil too

[roop]

Yes, check the vacuum hoses for splits. I went through two sets in the 3 years I had my GTI 8v. Also, the throttle box/dealie/butterfly thing at the end of the air intake from the air filter got all clagged up with crap. Sprayed a load of carb cleaner in there and it fixed the stuttering on my car, although to be fair that was at lower speed / pulling away...

[roop]

I forgot to mention, if you're around the North West then the guys at Dubsport are superb. Got my car down there and they fixed all sorts of niggly things. Took them about 2 hours, reaplced loads of bits including full set of belts (cam, PAS, alternator etc) plus the vacuum hoses, rotor arm and the total cost was £100. Top Work. They know VW's backwards...

Ooh yep, check the rotor arm. They get tiny hairline cracks in them - enough to cause all sorts of mischief - well, it did on my car...

>> Edited by roop on Thursday 28th October 11:26

[duke thrust]

Thanks guys, it's also been suggested that it could be either the ECU or fuel pump relays - sounds plausible to me, any thoughts?

[Pickled Piper]

Personally, I'd change the cap, rotor arm and leads next. No technical rationale, but purely on the basis that they could be the culprits and are cheap and easy to change. Buy your parts from German & Swedish, if you are not doing so already.

You may also want to browse on the Clubgti website as it's a common problem and there is a lot of good information on the site.

Good luck.

pp

[duke thrust]

Just to add a bit of info to this tread in case it's of any use to anyone else:

I bought a new ECU relay as according to the GOlf GTi boys this was the most likely culprit. As soon as I left the VW dealership the problem vanished. The only thing is is that the relay isn't fitted, just placed in the glovebox for fitting later that day.

So I didn't find the problem but it cost me 50 quid for a new coil, never mind....

Most likely to be damp somewhere I'm guessing.

[steve_D]

I have a new 'squeel free' fan belt doing the same thing, sitting in the glove box.

Steve