Stutter At 1700Rpm

[toolie72 67 1 Cars]

On light/part throttle got a stutter (only way I can describe it) at 1600-1700 rpm,any gear

When booting it, it's clear

I'm putting it down to tps, I have a tested one on a polished throttle body but I'm waiting for polished manifold to come back to swap whole lot

Ignition system,rest of cars ok no issues, idles hot or cold (albeit Massey ferguson when still warming up,but doesn't stall)

Anybody got thoughts on my reasoning-good or bad, I'm a big boy

Cheers

[steve@cornwall 100]

Had a similar stutter on my gti which got progressively worse and had me pulling my hair out. Could set it all up and would be great for a couple of days and then creep back in. One day it was atrocious but seemed pretry obviously an intake air leak.Turned out to be a split hose from sad where it joins under manifold.

If you're about to swap manifold and throttle body just check all pipes etc at same time and no doubt it'll disappear.

For good measure you could ad some new thermal paste to the ignition module (or renew the module) and give a good ignition service too. Just in case

[petert 589]

Hi big boy. It might be a mixture issue. Try richening the idle mixture on the AFM.

[toolie72 67 1 Cars]

Cheers, will try afm first-I did richen it one turn last time I checked plugs as I felt they were TOO clean!?!?

It's a donor engine I changed over Christmas hols so I used the best hoses that I had in my stash but I'll check them when changing manifold. It feels almost like the hiccup you get when you're about to run out of petrol-3 coughs and picks up again

I was just blaming tps as its about it's cut off point but it's not there on full load

Ignition systems pretty much replaced, haven't touched module since I bought car (1996!)

I do clean everything out with carb clean pretty religiously (or thrash it)

Might try running it with tps disconnected-if no different then it's ok

And yeah forgot all about the pipe under the manifold-doh!!

[toolie72 67 1 Cars]

So richened mixture, took it out for a wee run-much better

So now I'm thinking an air leak is probable-masking it now with richer mixture

No major works been done before it appeared so I can't see how mixture requirements would change all on their own so optimistic Paul thinks it must be a split/pin hole hose

Hahaha that's me shot myself in the foot now!! Investigation/can of worms to follow

Thanks for help, more grief to follow no doubt tsk

[toolie72 67 1 Cars]

Flapping air flow meter was the cause

Cleaned up meter and resistor track etc-noticed that spring was buzzing when flap shut

Marked the disc-wound spring up a couple of notches until it didn't buzz/rattle

 

So far so good (fingers crossed,sphincter clenched,pound coin in the wishing well,you get the idea)