Our 914 isn't cooperating Options

[LeNeon]

Hello!

We're enjoying our 914 1.7, but a few issues have developed:
- Our windshield wipers failed (yay, we'll have to remove the fuel tank...)
- The heater had been (wrongly) restored, we'll see when we drop the tank
- some localised rust... not too worrying though.

But now we have a bigger issue, and we don't understand where it might come from.
When accelerating under load, the car was "choking" at 3000 rpm. We adjusted the push-rods, as well as the injection a few hundreds of kilometres ago, it helped, but didn't solve the problem.

Now, it's becoming really worrying, the car really hasn't any power. It's impossible to drive it, because the car just doesn't accelerate. When at idle though, the engine is fine, only a few hiccups. And when without load (wheels in the air), we can go through the gears and rev without any problems...

Thanks in advance for your help!

Peace