Jerking in traffic

[guest7032]

Hello all,

This is my first post on here but have been reading the posts for a little while.

I have a 2004 1.4 8v sohc on 152k miles and it's a fantastic car, We have named it the mighty jazz 😀.Brilliant little car which is excellent on fuel and can get all my bikes etc in but It has a few little problems like the gearbox whine which I will do when the clutch needs replacing and the rear wheel bearing goes every couple of years.
It has one fault that I can not seem to figure out what's causing it. It's mainly at slow speed when pulling off and really bad in slow traffic. I'll pull off or moving very slow (idle in first so just moving)and as i touch the throttle it suddenly jerks and starts kangarooing like a learner driver. First I just put it down to me but now I'm convinced it's something the car is doing. It's like the throttle drops at approx 1200-1500rpm. If I give it higher revs 2k ish and slip the clutch a bit more it's fine but I don't like doing that.

I also have had a few times when accelerating say in second gear with mid throttle a slight drop in power then all of a sudden it's like a turbo kicks in and it just goes. No missfire and its not a massive drop in power just a slight hesitation and doesn't take long for it to clear.
Anyone heard of this one before?
Also, I was reading last night about rear spark plugs. Does my 8v sohc version have 8 plugs? I've changed the plugs many times but have never seen an extra 4.

Thanks Jon

[Jocko]

Welcome. Your car sounds exactly like my 2006. Firstly, plugs. The DSi in the spec stands for Dual Spark ignition and it does indeed have a second set of plugs to the rear of the engine.
I also have the problems you mention regarding the kangaroo petrol. It seems to be down to a very sensitive throttle. You can in fact get a device that allows you to control that, but it was too pricey and a bit of a guddle to fit, in my estimation. Very thin soled shoes help!
Touch wood, but I have never had any wheel bearing problems, but I do have the gearbox whine. Seemingly, it can run for ever like that, so unless the gearbox ever has to come out, that won't be getting done. It will be easier to fit a louder stereo!

[guest7032]

Thanks for getting back to me jocko.

Where are these other plugs fitted? They right down the back?

[culzean]

Also, I was reading last night about rear spark plugs. Does my 8v sohc version have 8 plugs? I've changed the plugs many times but have never seen an extra 4.

Thanks Jon

The rear four spark plugs on the Jazz are the best kept secret in the motor trade  .  I doubt if many get changed even if you car has been serviced by a garage,  the gap gets bigger,  the coil pack has to keep upping the voltage to jump the gap and before you know it a coil pack fails.    Replace the plugs and this will show if any of the coil packs needs replacing.


Jerking at low speed can also be EGR valve stuck open,  but plugs are the easiest to do and if you say you have never replaced rears they will be prime suspects.

[Jocko]

Where are these other plugs fitted? They right down the back?

They are at the back, but on our Jazz easier to get to than the front ones, believe it or not. You can see the tops of the four coil packs, bolted to the head.