Juddering after some work

Hi All,

Have just had kingpin done on driver's side, and new power steering belt. I don't know if it is just coincidence, but in this same week I am now experiencing a small but noticeable loss in power when accelerating, and have a judder when I'm in the lower gears (not on motorway).
I'm no mechanic, but the parts that have been changed don't seem like they would cause these symptoms? 

I am waiting on a new IAC valve as I am having the "almost stalling at lights" issue. Will wait and see if this is contributing to it.

Spark plugs are less than 6 months old, and I don't rack up a lot of miles. I had to change one ignition coil a while back, and while the part numbers were the same, it isn't a perfect identical copy. If anyone has a link to a guaranteed match, I would love to know so I can rule that out too.

Any suggestions for things to check would be much appreciated!
Thanks!

Just editing to say. Gen 3, 2003, M13A, PS no AC.

Could be a coincidence, but then they also say the last thing you touched is probably the issue. 
Juddering
Jack the front wheel that's had the kingpins changed and feel for any play. Also rotate the wheel to check all is smooth, no odd noises. Also check if any  balance weights have been knocked off the wheel, or swap them front/rear see if anything changes. 
Powerloss
Is the Ac working in that the electric clutch on the Ac pulley engages/disengages when switched on off. 
M

Thanks.
No Aircon in mine, though, so won't be that.

I'll get it up and check the wheels. 
You have reminded me though, I do need the tracking done which may explain the judder, but not the loss of power. 

Is the judder a misfire or is coming from the wheels/drive train? Slip the clutch when rolling, coast and see if you can feel any judder.

If it only does it under power and feels like a misfire then might be a long shot, but did the vehicle stand for a while when the works were done? If it did it could be

- Battery very low
- Water in the fuel tank
- Brakes binding

Hope that helps

Robin

Will make mental notes on my way home from work, but I first noticed the judder when accelerating. Like I said, not noticeable when on the motorway, more so in gears 1, 2, and 3.
I part work from home and don't go far on the weekends, so the car is often driven less than 10 miles a day 3 times a week, with the occaisional blast on the motorway to Liverpool. The kingpin + belt was changed friday evening (brother in law is my saviour mechanic), and driven home, but then left until tuesday. 

I had a worry about the battery. Seeing a engine draw/rev drop when I connect my phone to the aftermarket stereo via bluetooth (which could also just be coincidence with the already dodgy IAC). I don't know the age of what's in there, but it isn't stock; it's a halfords one. I am wanting to put in an aux battery for camping etc, already installed the battery tray and have been told to consider a new battery when setting up the split charge system. Had this car over 12 months and never had a flat battery (touch wood).

Thanks for the advice. Will check everything suggested so far.
 

Sorry about AC, did read it, but my mind swapped to AC belt as I typed. Possibly an age thing or the fact I was sitting in the hot sun as I typed wishing I had AC

When my Gen 3 started juddering under acceleration it turned out to be the crankshaft pulley de-laminating and the outer section wobbling, I couldn't figure out what it was until one day I was pulling away from some traffic lights and the vibration completely stopped.

And the ignition light came on.....

The outside of the pulley had dropped off.

If the car still has operational vacuum hubs check the pipes have been fitted back to hub, easy to forget if distracted. Not sure what impact this will have on the engine operation if any, but your 4x4 won't engage and it's worth a check.

@Scimike - 4x4 hasn't engaged since I've had the car. Assumed leak in the pipes along with signature flashing lights. Need to get manual ones! I will check this though, as my BIL definitely mentioned something to this tune since he knew the vacuum system was broken.  

@facade - Hope it's not this!

Wouldn't you all know, that it didn't judder at all on the way home from work, or this morning. Felt it jolt a little after I put my foot down when I was out and about last night, and power loss has gone completely since then. Thanks for all your help! Will continue to track it (along with fix all the little issues!)