P38a injection (or ignition) problem

our p38a a problem, rough idle, rough on load on petrol. On LPG it's also rough on idle, but during load it's better. This is a Bosch type engine

Took out the spark plugs; cylinder #3 is way too black, and cylinder #5 looks brand-new. Both are sparking OK. Already replaced HT leads and coils, triple checked everything on the ignition side. Ran the engine with the spark plugs removed. It seemed like no petrol was coming from #5, but it's kinda hard to tell

Replacing both injectors just to rule them out is kinda costly Swapping them around is quite a bit of work though because the top of the inlet manifold has to come off (and the LPG that's mounted on top of that).

Has anyone seen something similar to this? What's would be the best course of action to attempt to diagnose/fix this problem?

Edit: I did some major work (a tappet was broken, not worn but really broken) on the engine, and the injectors are probably not back in the spots they came from, could something as bad as this be caused by not resetting the adaptive fuel values?

have you checked the maf sensor?

How can I check that / rule that out?

srijken said:

How can I check that / rule that out?

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just unplug it if no difference then you likley found your problem

I should expect the engine to run worse when the MAF functions correctly and I unplug it?

srijken said:

I should expect the engine to run worse when the MAF functions correctly and I unplug it?

Click to expand...

if you dissconnect it and no difference in the running of the engine then suspect the maf is faulty. it will be obvious once you dissconnect it give it a go

Disconnecting it caused the engine to stall or run with irregular rpm during idle. Probably something else wrong then. Is there a way to rule out a injector that's leaking fuel into the cylinder?