Could have a lots of causes.

First you should check for spark after the engine died and take a look at the spark plugs. Dry/wet?

When they're wet there's something wrong with the ECU, the twin coils or the wiring.

When they're dry the K-Jetronic is the cause. ->
Don't think it's an air leak. Engine would run bad all the time and not just after 10 minutes.
Are the fuel lines connected correctly to the metering unit? Usually you can't do anything wrong, but I've seen a lot of things... Did you keep the fuel lines and the banjo connectors?
Have you forgotten to connect any connector of the wiring loom? Especially warm-up regulator, temperature switch AND: overrun cut-off valve and the sensor on the throttle body. OR: Did you mix up the connectors of some of these devices? Usually the'yre color coded.