My wife has a 2006 monte carlo (lt i beleave) and its acting weird yet again she said its reduced speed even if its floored it will only go like 20 mph...she took it in last year and it didnt do it when it was in the shop... anyone know what this could possable be? it has i beleave less than 40,000 miles

 

So in otherwords your saying its wraps up?
RPMS go way high, car goes no where?

Is it doing it everytime? Or is it random?
Is it right after she starts her car and puts it in drive for the first time?
If she "wraps" it up, then slows all the way down (a stoplight, stop sign) does it then allow her to floor it?

It the above is all true, O2 Sensor, is a huge possibility, i believe.