My car is the same. BUT, I have plenty of power and no CEL or anything. I was under the impression that the engine PCM doesn't let the RPM above 4000 when in neutral. My sable was like this too. In gear, it went to red line. in neutral, the PCM cut the fuel at 4000 RPM. I don't doubt the other posters had problems, but if your car is running o.k. otherwise, I think it is just the PCM doing what it is supposed to. My secondaries open in neutral, but 4000 RPM is it. In drive, it pulls hard right to redline. I have 28000 miles and the car is in good condition. Maybe Terry H. or someone more familiar can verify this before you get crazy.
Engine RPM/Vehicle Speed Limiter
The powertrain control module (PCM) will disable some or all of the fuel injectors whenever an engine rpm or vehicle overspeed condition is detected. The purpose of the engine rpm or vehicle speed limiter is to prevent damage to the powertrain. The vehicle will exhibit a rough running engine condition, and the PCM will store a Continuous Memory DTC P1270. Once the driver reduces the excessive speed, the engine will return to the normal operating mode. No repair is required. However, the technician should clear the PCM and inform the customer of the reason for the DTC.
Excessive wheel slippage may be caused by sand, gravel, rain, mud, snow, ice, etc. or excessive and sudden increase in rpm while in NEUTRAL or while driving.
This is from the Ford Tech service CD. This is what you probably had.
Good luck
