Plugs were out, yes. Engine doesn't have higher compression then normal I'd think. Values were between 12,8 and 13,5 (bar I presume).

 

I've ran 2 tanks of injector cleaner, now is my first tank without. I'm halfway through it and now it's acting up again at idle. Idle drops really low to about 400-500rpm and feels like stalling. Has stalled on me once now...

 

In my case, it's not the battery or alternator, but you should have the alternator checked if you didn't so far. Very easy and usually free in any car garage.
(just thinking alternator is weak and does not provide enough power to the coils)

 

I've had the same thought actually. Everytime the rpms drop and pick up again, I also notice the instrument cluster lighting goes weaker. Don't know if that means anything though.
I always drive with my lights on and also turning the A/C on doesn't make a difference.

I would also think a weak alternator would give troubles in higher rpm ranges as well? Battery seems to hold it's charge.

 

Well it's been a while...

A lot has happened and been tested and so far still little to no results.

Past weekend however, someone made an interesting discovery. With the engine running, he took the oil cap off and noticed a petrol smell and something with the pressure.

He then took his exhaust sniffer and held it above the oil filler opening... and sure enough, very high HC values. Meaning unburnt fuel is mixing itself with the engine oil. This is probably also why the ECU thinks the car is running rich and why it isn't running as smooth as it should, because fuel vapors re-enter the intake system.
He said this probably means my piston rings are worn. Compression and smoke is okay however.

He also said it isn't something to worry about, as long as I regularly check my oil and most importantly change it more often.

It might also help to install an oil catch can to increase driveability. It won't solve the initial problem, but it should make the engine run better.

Any thoughts on this?

And links to oil catch cans and how to install these? Will a normal ebay example do just fine?

 

I can't believe you're still dealing with this. I would have ditched that car months and months ago. GL.

 

Have you checked your wiring when the engine swap was done?

Check the wiring on the MAP sensor and TPS sensor. If they're the same plug, trying switching them out and see if that fixes anything.

 

Wiring should be ok, readings and voltages are normal.

 

Not the map sensor, not the FPD (on the fuel rail, I was missing the cap+screw), TPS sensor gives the normal voltages and keeps them constant for any time when the pedal is pressed. I'm leaning towards an electric problem...

Yes, I still haven't found the problem as well.

 

take a picture of your map sensor, i wanna see the colors on the wires that are plugged into it.

I'm still thinking about a switched plug.