Ok. First off let's all hope this is an ignition problem rather than an injection problem. Why because at those RPMs if you injection is cutting out, or running lean, it will be harder to fix and could cause some real problems.
Also everyone lets remember that this is not an electronic ignition we're dealing with. It's a mechanical. Correct me if I'm wrong but it has a Bosh K-Jetronic injection system. Here's a quick explanation of how it works:
"An early fuel-injection system developed by Bosh that uses mechanical means to meter the flow of fuel to an engine based on the amount of air flowing to the motor. A primary component of the system is a hinged air-flap that hangs in the airstream in the engine's intake. As airflow to the engine's cylinders increases (due to increased engine speed) the flap is deflected which allows more fuel to flow into the engine.
An improved version of this system known as the KE-Jetronic system, retains the air flap but incorporates electronic controls and sensors which aid cold starting and produces more precise air/fuel ratios."
Go here for a full overview:
I’m pressed for time but I’ll come back to this post before I reply to any others because you might have a big problem here. Then again you might have a small one. The big one would be one of your injectors isn’t giving the cylinder enough fuel. Notice I said enough. We’ll hope that if it’s an injector it’s cutting out and not starving the cylinder. If it’s not getting any
fuel no big deal. If it’s not getting enough
it’s running lean and that can mean you’re burning a hole in either your piston, rings, cylinder wall, or all of the fore mentioned. Or it could be the AFM isn’t operating properly and is giving the ECU the wrong signal and therefore the wrong amount of fuel is being delivered.
In short play it safe and don’t drive this car hard (if at all) until we get this sorted out. As I said I’m hoping it’s ignition and you’re just not getting enough spark to one of your plugs.
When was the last time this car had a tune up? New plugs, plug wires, cap, rotors, ect…?