1.6 GTi - Idle / Hesitation Problems

Hi All,

Got my 1.6 GTi back on the road yesterday, but was experiencing hesitation and very low idle after 10-15 mins of driving. Anyway, got it up to a mate's garage for a proper 'tune up'. As part of this, we checked the timing (again), which was spot on. Next we used a wide band lambda and got the fuelling bang on, and tweeked the idle speed down to 850-900rpm. Drove it 40 miles home and it felt great, without hesitation.

However, took it out this morning, and it's almost like its reset to it how it was before the tune up. It's hesitating and exhaust it popping and trying to idle but for some reason it's now trying to idle at 500rpm and it's hesitating again. Any ideas why it might be "losing" the settings?? I've had a quick fiddle with the fuel again, but no luck.

Cheers

Matt

PS: hesitation only happens when cruising along a a steady speed, not under acceration.

just a thought but have you checked your fuel pump and filters?

Fuel pump is new, and all filters replaced in last couple of weeks.....(tank, filler neck etc. all done too)

have you checked plugs hts etc right through

i know prob daft questions and you may have already done but trying to rule out all the easy stuff

Yep, plugs new and gapped, new HT leads, dizzy, rotor arm….

I think the hesitation may be to do with the fuelling set up……but having read a few posts on the forum….could my idle problem be related to a sticking or poorly operating Warm Up Regulator? i.e. engine idles fine when cold and warm, but when hot (after a run), it causes a very low idle….