For some reason my motor is cutting out at 3900 RPMs and cannot really get it to go more then 4100 RPMs

This isn't even close to red line, any ideas?

What conditions is this happening under? Revving it in park? Is it just hanging at that RPM while trying to accelerate, and won't upshift?

In park still working on it

That is normal. There is a rev limiter in park, and neutral I believe too. 4k sounds about right.

Ok Thanks rjolly that helps there. Its odd tho cause the 2 lesabres that I have worked on didn't have that limiter. Guess its a Pontiac thing LOL

What years were the lesabres? My 93 doesn't have it either

Both of them are 2000'* also and I worked on a 2003 that didn't have it either

I'd be glad it has it, revving the rpm'* up that high while in park is probably not the best thing to do to your motor.
It is odd you have come across 2000'* and up without rev limiters, I am not sure the year they started adding them, but I am pretty sure all 2000'* and up GM'* should have them, unless somebody raised the limit in the PCM.
My 96' PA has one.