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VZ ROUGH IDLE. Huge miss when driving

Zach05vz

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Hey! Brought a vz cheap that has been off the road for a fair few years.
replaced coils and plugs, fuel filter & pump.
Then put a scan tool on it turns out it was missing the o2 sensors.
vz 172kw has 2 4pin o2 sensors on them so put them in.
Running better but still rough idle and massive miss. Really sluggish.
Then did the MAF sensor.
STILL NO LUCK!!
Any ideas?? Thanks!!!!
 

greenacc

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Injector fault is my guess since you already replaced the coils.
While you're at it check the pcv tube is clear and you can see daylight through it.
 

keybored68

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Mine had a rough idle after I pulled it apart to replace the timing chain. In the end found the cause was a loose earth wire connection to the engine body (on passenger side down below oil filter). My fault that I hadn't done it up tight.
 

Zach05vz

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Cheers I’m going to put new injectors and clean the rail next. Also check the pcv tube while I have the manifold off.
see how that goes. Thanks fellas!
 

Aus78Formula

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I have a similar intermittent fault with my VZ. Occasionally starts and runs rough with a misfire, then comes and goes while driving. It only started a few days ago so no time to get sorted. Got it scanned and came back as fault with injector 5, or similar. But mechanic said often it's not the case, and code is thrown up by failing engine computer. I will get it checked by a specialist once they all open again to see what they say.

And 1400 bucks later, including new computer, plugs and leads and coil packs swapped, it was only corrected with a used set of injectors. Sometimes it doesn't matter what the advice is, or their experience, can still be wrong. Just annoyed they didn't try the injector swap on day 1 as per fault logged. They tested them via computer load but found no fault.
 
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Jolls

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It would be a good time to check and clean the earths too.
 
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