Engine surging at higher RPM's

Good morning,

Two things come to mind to check to start.

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

1. Fuel pressure. you can check the actual pressure at the valve right by the power steering pump. Check the pressure key on, engine off and while cranking. It is number 3 in the picture below.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

2. catalytic converter. it may be clogged. This is a common reason for hard start and not going above certain RPM and speed.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

You need a back pressure gauge that goes into where the upstream O2 sensor is located. You start the engine and measure the back pressure. If it is above 1.5 lbs, it is no good.

Roy