MY 99 ford Taurus while in park,,, when I hold the gas pedal to the floor, will only rev to 4000 rpm's and then drop to a normal idle then it go back to 4000 rpm's. This will keep doing this as long as I hold the gas pedal down. but when while driving the car I have no problems, it runs fine
Well, you did come off as kind-of trollish and it can be taken either way, but everyone's entitled to write an awkward sentence now and then.
They build safety systems into new cars, and the rev limiter is one of them. The computer knows the car is in park, and while revving it to 2000 - 3000 RPM while parked is useful to get full alternator and air conditioning output, any more than that is simply asking for big trouble if someone drops it into gear...
If you ease into the gas it will take the RPM's up to the limiter and hold right around that point, and not impose a hard fuel cut. But when you stomp the pedal flat to the floor and hold it, the computer figures it's an accident - something fell on the gas pedal. The 'drop back to curb idle' behavior is the computer trying to protect you from yourself.
Be careful - you can still miss a downshift and zing the engine up to 15000 RPM and break it. ($3000+ repair bill if you do a real good job like "ventilating" the block.)
The computer has control of the fuel and spark, and on an automatic transmission there are safeties to prevent a downshift engagement that would over-rev the engine. But on manual shift cars the computer can't push the clutch pedal in for you to prevent that from happening.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.