m20b27 engine stuttering and holding back, temperature jumps

[MWe]

Currently experiencing a problem with my engine.
It is a m20b27 stroker with 1.3 moronic.

When driving the engine sometimes stutters, most noticeable during acceleration, but during constant speed it sometimes feels like it's holding back as well.
Engine does manage to pull through the revs but a half gas it's worse than when I floor the throttle.
During this stuttering the temperature needle spikes to about 3 quarter, so just before the red area, but the strange thing is that is jumps to high instead of creeping.
Another strange thing, when I shift gear, the temperature jumps back to the middle sometimes.
With no load the engine revs freely.

I suspect a fault in the engine loom, a shortage or bad connection, but maybe someone has experienced similar problems.
Anyone has a clue to where to look first?

[redlightpete]

Check the circular connector under the intake manifold. It contains the injector wiring and the temp sensors, so when the engine is moving under load, you’ll get intermittent misfires and temperature readings. Coolant leaks at the throttle body tend to leak onto this connector and corrode it.

[MWe]

Currently checking that one indeed, plug c191 it’s called I think.
Had the similar feeling that might be it but maybe someone experienced the same problems and knows the direct solution.

[MWe]

So that plug was cleaned en reassembled, didn’t see much dirt in there. Problem still ongoing unfortunately.
Easy on the gas seems to work, full throttle also less holding back. At half gas or slightly accelerating the problem is most noticeable. My suspicion is the AFM now

[zaq123]

I still think it's C191 connector, main harness side or injector harness side. Fueling issues and temp sending unit issue at the same time, gotta be c191. How did you check it? As a min, I'd put ignition on and go bending moving harness around and have someone else watch if it affects the temp gauge, move c191 around including that small wire from the harness to the temp sending unit and temp sensor.

[MWe]

I was about to take a look at the AFM but did the same test as you described when somebody was nearby.
So with the car running I had the other person looking at the temp gauge on the dash and I wiggled on the connector a bit, pushed in the rubber grommet as well, and the temp gauge went berserk.
So currently in the process of replacing that connector with a DT-connector. I went with and DT04 8p version because I thought there were 7 wires, apparently there are only 6.
So the red/white cable, feeding all 6 injectors, will get two wires.

The harness is a bit short, so I went with a pigtail.
Hopefully I get it fixed this week, will report back if it solved my problems.