Strange missing

[c1sps]

For the past couple of months I've had an odd juddering, as though the engine has a slight miss, in low revs (2000 - 2500) and lightly applying right foot. Started only when the engine was hot.
I've now had full 12000m service (including tappet adj) and a ne set of leads - still the same judder, but now from cold as well.
Anyone any suggestions for the cause - hoping I'm not starting another rebuild topic here ?

[scooterscot]

Does the engine pick up on hard acceleration? Does the missfire become worse on a steady throttle. Try running in top gear at 40 mph on a steady throttle, then try it again at 50 mph on a steady throttle. If the engine runs ok for a few seconds at a steady throttle then has a sudden missfire and this problem has been there for a some time it is possible that you have throttle wear. Give us a call and I will talk you through some tests as there are many reasons for poor running.

[c1sps]

Its only happenning in relatively lower revs - no apparent loss of power, but I think fuel comsumption is 20% lower - in low gears the jerking is more noticeable, particularly if I take my right foot off completely !

[nelly1]

Sounds like the throttle pots to me.

Either that or the throttle spindle bearings are worn and need re-bushing.

A quick check with the diagnostic software should tell you.

[c1sps]

Expensive?

[so called]

c1sps said:

Expensive?

Hi c1sps,
I have just had my throttle bodies fitted with roller bearings. Mine is an early Tuscan without any bushings. It is costing 600+VAT: this includes machining of each body on both sides and 12 roller bearings.

If yours is already bushed, then maybe its only a matter of pressing in new bushes.

[Whitey]

as scooterscot says, it could be a number of things, and as it's not your leads as I suggested on another thread, I would take it straight back to whoever just did your 12K service and get there opinion.

[c1sps]

I had been wondering if it could be something as simple as the coil - or is that wishful thinking (in view of the cost ?)

[Whitey]

what year and miles has your car done? I reckon it's to do with your throttle pots and/or throttle bodies, but the coil pack is an easy change.

Just get it back to whoever serviced it and they can get it onto the laptop to check your throttle pots first.

[c1sps]

52-plate Mk 1 20,000 MILES - back to garage, but not until Monday unfortunately. Will diadnostic programme show a faulty coil or throttle pot problems ?

[c1sps]

And why is my background always this bl**dy buff colour ?

[tobeee]

c1sps said:

And why is my background always this bl**dy buff colour ?

Because you started the post!

[c1sps]

No - it happens even when I reply to another topic ! Perhaps its some sort of summery tan coming through........

[c1sps]

So 800 miles in Devon and she never missed a beat - could it just be some dirt in an injector ? Whatever it was, it's gone !