I'm getting these symptoms second hand for a 2002 Le sabre Limited. It will do 45-50mph on hiwy without touching accelerator. I've been told accelerator is not showing any depression when driving and butterfly no open in park. Then put in neutral rpm's come down then put back in drive and it repeats. This wasn't as bad to start then got progressively worse and now constant. When in park idle ranges up and down 1200-2000 rpm's. All these symptoms occur with the cruise and A/C on or off.
Check engine light has never lit up. No codes. All sensors
have been monitored with normal readings.
Throttle body has been off and cleaned. MAF, IAC, TPS, MAP, PVC all changed. Plunnem was checked for cracks when T-body off. Ether sprayed all over engine with no change in idle and no vacuum leaks can be found.
Cranks and starts normal. Does not miss or hesitate. Any Ideas?