Hi again guys. **Car is an '03 Verada KL Xi

Basically, my engine was misfiring when stopped at traffic lights etc so i figured i should change the spark plugs. When i pulled the front plugs out, while they were definitely old, there was oil on them too. I assumed the back ones would have the same thing so i decided to get some gasket/tube seals and change them while i did the rear plugs. I also did the ignition leads, as i didnt want to have to go back there again for a while.

Anyway, after completing the job, the problem is still there but seems a little different. It seems more consistent now, rather than random misfiring when stopped, it is constant(when stopped) and the revs move around slightly every time it misfires, basically constantly moving between 500-700 where they didn't move at all with the previous misfiring.

I removed the front plugs to check for oil and there wasn't any, so i assume i haven't bungled the tube seal job, and rocker covers aren't leaking, ignition leads seem to all be firmly in place on the distributor, and i changed leads 1 by 1 to the sames spots to ensure firing order is right.

Spark plugs are NGK regular in front, platinum in back.
Leads are Bosch super sports leads.

unless a lead or plug is actually faulty, only thing i can think of is that i did something wrong with the plenum removal/re-install, but as far as i can tell i put everything back where it came from and wasn't too rough with anything(it was my first time removing the plenum though).

Any help greatly appreciated thanks.

Check the plug leads with a multimeter, one of them may be high in resistance.

IF OK: check distributor cap for dirt, cracks.

IF OK: Check compression, may be a poorly seating valve.

Randomly started raining before so had to delay some checks, anyways,

Tested the front bank plugs but am unsure what my settings should be on the multimeter.

when i set the multimeter to '20k' in the resistance section, all of the leads came up between 3.5 and 4.5, if i change the setting to 200k, it basically moves down a decimal point: .35 - .45
If i change the setting to 2k, it just says 1. for all leads(which is apparently the default value when it isn't reading anything).


Second thing, i would just like to confirm the lead placement order. I have made a dodgy paint picture to show which lead is going from which point on the dist cap, to which spark plug hole. Made the picture use colours for each position so its less confusing.

http://imageshack.us/f/69/leads.png/

Would like to know if this is the proper order.

Will check the distributor itself tommorow, thanks!

Maybe your injectors are cruddy? I had similar problems, and got the injectors cleaned and Voila! - smooth as....

Resent:
I just had a look at your sketch. I think your plug leads are wrong. It is confusing. The firing order is 1, 2, 3, 4, 5, 6. The distributor direction is clockwise when viewed froim end on (as per your sketch), and No 1 is immediatley past the lug on the cap. The only doubt is which plug is No 1 , but I think you have No 1 correct. I think your No 5 and No 3 may be crossed. Sorry - I don't have access to the manual (the car isn't here for a pitsto) so I cannot confirem. Maybe others can verufy what I have said?

firing order is...
rear bank: 1 3 5

front bank: 2 4 6

the dizzy is marked from 1-6, shouldnt be able to go wrong now :)

Does incorrect lead order sound like it would give me this misfire issue? I figured it would be much more severe.

I have a copy of the PDF manual but all i can find is the 1-6 firing order, not which spark plug holes they go into though =/

Are those numbers for the spark plugs holes definitely correct Ziek? Just want to confirm before i swap cables around

Standing at the driver's side of the engine - ie where the plastic cam belt covers are - the left or rear bank is 1,3,5 with 1 closest to you, the right or front bank is 2,4,6 with 2 closest to you.

As above, the distributor cap is numbered.

Can't go wrong with the original leads due to their length.

Just checked the distributor cap and the numbers go anti clockwise around the cap. So looking at the picture i made, starting at the red circle(this is the place of the actual number 1) and going anti clockwise - appears they are all in the proper order.

Time to actually check over the cap for problems :(

Okay so i got down to where the cap is and seems there was some oil around the outside at the bottom, cleaned it off but couldn't find any leak in the area at all so unsure what that was about.

The cap itself seems okay, but the rotor button tip seems worn/corroded, i took a pic:

http://imageshack.us/f/266/dsc0007xn.jpg/


Anyway, i put everything back together and started the car, switched to drive(sitll parked in driveway) and the car seemed to be running very smooth. Went for a drive around the block, pulled over to check the idle, and there it was again, car jumping and jerking as before. Seems possible that it started to happen as the car warms up?

I had that issue with a magna TR when i stopped at traffic lights or slowed down and turned a corner the engine would stall. Mine was a faulty idle speed controller. not sure if its the same issue but worth a look after all the plugs, dist cap and leads have been changed.

ok, going by that pic of that rotor button, it needs to go, i would say the contacts in the dizzy cap isnt all that crash hot either. so in conclusion, looks like its a new rotor button and cap time.

Just took the ISC thing out...was oil in the plug/connector and cleaned it all out. also the bit where the ISC actually sits in was filthy so gave it a clean.

Put back together and tested, still the same :(

I had a similar issue... Mine was caused by the oxy sensor. Replaced it, all sweet! :)

Just fitted a new distributor cap and rotor, went and did the same driving tests as after fitting each other part....and she is smooth as a bird at idle!! WOOT!

Revs were nice and still while idling, sitting at slightly over 700 and not a single miss from the engine. Thank you so much to everyone that has given input, lets hope she lasts a few km's!