INJECTOR MISSFIRE ISSUE

[Akeelk]

Hi I have a 2008 vw golf mk5 GTI with a missing issue and I have done the following -

1. Removed and sent off the injectors for a clean ( 2 came back with unuseable)
2. Order 2 refurbished injectors  (still missing on random)
3. Ordered 4 injectors from China with bosch stamp and part number (still misfire on random)

I would like to know what is the best thing to do next

Many Thanks

[GreigC]

Hello, few questions to try and help.

Have you scanned the car for fault codes? If so what are they?

The injectors you got from china… are you sure they are genuine?

When you done the injector service did you clean/blast the valves?

[blingsta]

have you checked or changed the spark plugs or coil packs?

[pudding]

It's a waste of time using anything other than brand new, OEM injectors.

They are mechanical parts that wear out. Refurbed ones will last a short while but only new OEMs will guarantee another 80-100K reliable use.

[MrDoritos]

Check that it's not unbalanced cylinders, bad coils, bad plugs, or carbon choked valves. Personally I had a bad injector on cylinder 3 that caused a misfire only on idle with A/C off. I would never have had needed to replace them and new injectors are up to $1000 from VW, but it bugged me enough to bite the bullet eventually. I figured since compression was fine, and I was using new plugs and coils, and I cleaned the valves, and the misfire was only on one cylinder it had to be an injector. Do not buy Ebay injectors. I made that mistake. Buy once cry once.