[Alfisto Steve]

Are you sure your not hitting rev limiter and tach is off. Have you tried running up slowly in first gear to 4k RPM and observing speedometer and recording speedometer reading when it cuts off and same in second?

Report your speed in first and second when it cuts out.

Is this a new used engine or a new rebuilt engine if rebuilt go easy on it and break it in correctly.

If used engine does it have new timing belt and safe to wring it out?

 

[Alfisto Steve]

Check Bosch connector to AFM for broken female wire terminal ends or unlocked terminals so wires not making good contact with pins in AFM.

 

[Alfisto Steve]

We had a similar problem with a 164L. It turned out to be loose grounds on passenger side of intake and that the intake was loose from rear valve cover.

Good point and if intake is not mounted directly to valve cover but on rubber mounts as later models are you have to have a grounding strap from intake to valve cover attaching bolt or directly to head.