7a hesitation, looking for wisdom

[varia]

I have this weird problem with my CQ 20v 7A
My CQ hesitates sometimes, like 1 or 2 cylinder are not running, CEL came up few times.
Pulled the codes, thats what i got:

Tuesday,14,May,2013,10:37:12:24117
VCDS Version: Release 11.11.5

                Address 01: Engine       Labels: None
Control Module Part Number: 893 906 266 D
  Component and/or Version: MOTOR       PMC 10
           Software Coding: 
            Work Shop Code:   
                      VCID: 254BF493BFBF333072A
5 Faults Found:

01249 - Fuel Injector for Cylinder 1 (N30) 
            31-10 - Open or Short to Ground - Intermittent
01250 - Fuel Injector for Cylinder 2 (N31) 
            31-10 - Open or Short to Ground - Intermittent
01251 - Fuel Injector for Cylinder 3 (N32) 
            31-10 - Open or Short to Ground - Intermittent
01252 - Fuel Injector for Cylinder 4 (N33) 
            31-10 - Open or Short to Ground - Intermittent
01253 - Fuel Injector for Cylinder 5 (N83) 
            31-10 - Open or Short to Ground - Intermittent

Readiness: N/A

Ive changed the fuel pump relay and it was ok for two months, but its back again.
I changed the relay one more time (brand new) new spark plugs, spark wires, distributor cap, rotor, fuel filter, fuel pump and new coolant temp sensor (back of the cylinder head)

Still the same, when its warmed up (ie fans kicks in temperature) often check engine light is on, seems one cylinder is not running, blue smoke.
few seconds later everything is back to normal.

Planning to change/check: wires, connector for injectors, MAF but other then that, im clueless.
Any ideas, advice?
Thank you
Chris

[Error404]

Yeah first check the wiring for the injectors as it tends to crack, and also check the earth eyelets on the back of the manifold, and the engine earth strap

[simon20vq]

Agree with ERROR. Does it happen more on a bumpy road? Have you checked for play in the dizzy shaft

[Mikes2]

Could well be a resistor pack problem.

Check the wiring's not damaged or touching the wiper motor

[Sleeper_Avant]

resistor pack seems the culprit to me,

id check the wiring to and from this first!

[varia]

I forgot to post that the car has 034 injector kit, no resistor pack, but checked the bypass harness, and its ok.

But a little update:
When i changed my spark plugs last week I noticed #4 was much darker then the rest of the spark plugs:




I installed new plugs and today ive removed them for inspection, again, #4




Looks like only #4 is the bad boy, but then why throwing codes for all 5 cylinder?
Checked the connectors, wires, everything looks normal.
Checked ground at the back of the head, seems ok.

What could cause that at #4?
Thank you!
Chris

[zefsider]

clear your fault codes...swap your injectors around... , note which cyl you put injector 4 , and try again ...might be the injector itself ...what are u using ? the 034 supplied injectors ? Did u get the bypass harness or DIY it ? If DIY, check your solder and / or the bypass plugs

Valve stem seals maybe in cyl.#4 ? Is that plug oily when u pull it ? ...... Is there a crack in the ceramic of the plug ? or did u replace them first off ?

Nice weather there BTW ?

[varia]

All injector are swapped, bypass checked.
Compression are: 1-200, 2-197, 3-195, 4-190, 5-187, No leak.

Its not oily, but dry powdery black carbon residue, to rich mixture, not burned properly.

My question is, why not burned properly:
Not good spark (strength, timing, etc)
or
Too much fuel injected, can an injector over spray?


Thanks
Chris
ps: i will check all the grounds, injector harness again today