A little agrivating fault !

Here I go trying to explain this one.
I have a old S reg jimny with the 16v 1300cc in it.
OK...when I drive ONLY SOMETIMES at about 55 - 58 mph with little throttle and move the throttle pedal off very slightly it goes as if it is running on 3 cylinders...or as if you have turned the key off momentarily.
If I press the throttle even a little it is cured until I let off a little.
This is not all the time ( Maybe once a week / fortnight )
Lower speeds spot on higher speeds spot on.
Done it for ages ! Does not bother me 2 much but I would like to know what it is.
If it was throttle position it would happen on acceleration or at the same position at lower speed or gears.

What do you think ?

I have not looked at it yet but I thought it was maybe a coil pack or cam sensor but at this point it does not make sense to change these due to the fact it only seems to happen when I am in a motorway run at a constant speed.

Thanks People for any advice you can throw at me !

Steve

hi mate mine does the same , but i thought it felt more like fuel starvation, or some water going through with the petrol, ie crappy petrol:angry:

Yea that's the initial impression as if the fuel is cutting off.
But its only at a certain speed and throttle position.

I can try the coil pack martin as I have a couple of sets here.

I am intrigued as I am not the only one with this problem.
Clyde says his does the same.

Steve

mlines wrote: It might be a coil pack, although the ECU seems pretty good at putting up the warning light if anything is wrong with a coil pack.

Martin

I agree, my signum did this and it was the coil pack....

Hi,
I changed both coil packs this morning and took it for a long motorway run to see if I could get the fault to happen again.
Drove about 15 mile no prob, then on the return journey I felt the normal hick that it does.
Well that eliminates the coil packs !
I fitted a cam sensor while I was under the bonnet as well.

Any more ideas lads ?

Its definitely when the throttle is in a certain position at a certain speed as like I say if I ease off a midges knacker or press it a midges knacker it stops at once.

It happened before as usual 55 mph !
Went up to 60 mph and perfect.....dropped down to 50 and once again perfect.
It is intermittent as this can not show itself as a fault for 2 to 4 weeks ( you sort of forget about it ) and then the little hick comes back. ( No engine light comes on and never has ).

Thanks Steve

hi does it feel like its running out of petrol and the rev counter bounces when you put your foot to the floor , if thats happening it sounds like its a cranckshaft sensor, mine did the same thing and fitted a new sencor problem sorted.hope this helps.

DAVE T wrote: hi does it feel like its running out of petrol and the rev counter bounces when you put your foot to the floor , if thats happening it sounds like its a cranckshaft sensor, mine did the same thing and fitted a new sencor problem sorted.hope this helps.

Hello.
No the rev counter has no effect with this problem.
Its hard to describe when typing but its like it begins to run on 3 cylinders but I do not believe it is for some reason.
If I move the my foot even a little ( and I mean a little, like the pressure of my foot within my shoe ) one way or the other it cures the fault.
It is only at a certain speed...if at the same speed and the motor is climbing a slight hill it will not do it.
I would say I have to be on flat road no uphill or downhill to make it do it.

Thanks

does it do it on a certain level on the fuel gauge at all, its just that im begining to wonder if mine is more through fuel, will keep an eye on mine to see when it does it again and will let you know

clyde wrote: does it do it on a certain level on the fuel gauge at all, its just that im begining to wonder if mine is more through fuel, will keep an eye on mine to see when it does it again and will let you know

Naah not really it does not matter how much fuel is in...I filled up today and the last time it did it I was about 1/4 tank.

Steve

Hi Steve, did you manage to sort your problem out? my 2006 seems to do the same, it is more noticeable at idle, every now and again the engine feels lumpy like it is on 3 cylinders

yes he did he sold it.