When I am in park, the engine can only rev to around 4000 rpm. However in Neutral, there is no restriction. Is this a GM restricting thing or is there a problem?

I do not know much about cars, so be kind please.

Gee to bad it won't rev to 7,500, then you could get a new engine, seriously rpms are governed in park and should be in neutral too.

When I am in park, the engine can only rev to around 4000 rpm. However in Neutral, there is no restriction. Is this a GM restricting thing or is there a problem?

I do not know much about cars, so be kind please.

The car's engine computer has a rev limiter; when there is no load on the engine, the RPMs are restricted to about 4,000. It's working as designed!