When I start the car the RPMs are really high & I have to wait to put it in gear, sometimes there will be a big clunk when I put it in gear then my trac off light comes on & as I start driving it feels like the transmission is going out. It does it randomly, more so after the car has been driven 15-20 min (in town)

SOURCE: high rpms, lights-service vehicle soon, Anti Lock and Trac Off

It may be the o2 sensor or the "A.I.T" sensor. same thing happened to me and we changed the A.I.T sensor

Johnny Massengill

• 345 Answers
• Posted on Nov 12, 2008

SOURCE: Transmission / RPM

These cars have a lock up torque converter meaning 4 gear going above 35 to 40 MPH, the engine and transmission lock together and turn at the same rate. I know that older GM cars had a plug that needed to be plugged into the transmission for the lock function to work on the torque converter and if you unplugged it the RPM's would run high as you describe. I have never had a 1999 Silhouette and I'm not 100% sure that these cars have that type of plug but it sounds like that type of problem. I agree with you. You know your car and I would take it to a transmission mechanic and describe your problem to them.

Good luck!

SOURCE: 1995 oldsmobile aurora automobile

You have a bad Parking brake, Brake, or Neutral safety switch. Not the end of the world on this one.

SOURCE: the abs light and traction

please tell me what to do when the abs light and service tractions lights show on my 2004 oldsmobile silouette van

SOURCE: transmission shifts hard when the trac off light comes on

youll need to scan for transmission codes. the trac off light is a default of the trans going into a default safety mode. Bad speed sensors and simple little bolt on items like that can cause the condition but only way to really nail it is with a computer.