Running poorly (again)

Heya! After my last post i had THE fix, drove the cabby perfectly for exactly 27 days!

Day 28 wont be added. It runs, semi.

If i start, the rpms are all over the place. It will settle at about 1000 and fluctuate alot. Up to 200 rpm.

Its drivable, but it doesnt drive well. Its hard to explain but ill try.

Lets say im steadily driving 80 (kmh) the car feels like once / twice every 5/10 revolutions it just doesnt fire on one or more cilinders.

Feels like it slows down, and immediately "shoots" forwards again.

I have replaced every single thing in the engine bay.

This all started after i put in new spark plugs, had 3-prongs in it. And just got a new ngk set of the same 3-prongs.

Ive heard some people say it needs a 1-prong, which i could understand because of the gapping.

Any help would be very very appreciated!

Many many thanks!

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Well if the revs are all over the place it sounds like a fuel problem, an air leak possibly.

Is it a gti. If so do you have muck in the fuel tank? Is the fuel pump making a lot of noise. Could be fuel starvation due to the internal filter on the fuel pump blocked ???


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Backinblack said

Is it a gti. If so do you have muck in the fuel tank? Is the fuel pump making a lot of noise. Could be fuel starvation due to the internal filter on the fuel pump blocked ???


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Heya, its a GLI, sorry for not mentioning.

Both fuel pumps have been replaced, sometimes the main fuel pump(under the passenger rear side) does make an awefull lot of noise.

You dont think its the spark plugs?

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cedar said

Well if the revs are all over the place it sounds like a fuel problem, an air leak possibly.

Heya! I have tested the incomming fuel pressure and thats right where it should be, and it holds without problem. I thought that i had fixed all air leaks. But i will check once more! Many thanks!

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If you have a rusty filler neck or general debris in the tank then new fuel pump will block up quickly. I’ve been there.

Take the noisy pump of and look in the suction end.  


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PXL_20230806_140621713.TS.mp4 - Google Drive

Here's a link to a cold start video! Might help

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Hi,

I have just put my 1982 Mk1 GTi back on the road now it is an historic vehicle. It has stood for 10 years.

It is missing firing especially when under load and will cut out. Pressure to injectors looks OK after new fuel pump fitted.

Fuelmetering unit leaking and replaced by one from my wreck 1982 GTi which has been standing for 20 years. Probably need to use a kit to renovate metering head.

I will replace distributor head, points [speed limited] and HT leads.

Any further suggestions please?

Back box needs replacing - will this effect firing?