Now that the weather is warming up in NYC I am getting this recurring
problem with my 1990 Grand Marquis 5.0 EFI.
When I come to a stop and change gears, like when parking and shifting
from drive to reverse, the idle goes way down and sometimes even
stalls. Most times it will go down and rebuild itself up again.
I have a new IPC and a new TPS. When running on the road or highway it
runs smooth at any speed with plenty of power and pickup. As soon as I
shift gears to park the idle drops to just above stalling.
During the cold winter here this did not happen. Just as it is warming
up it starts all over again as it did last year.
Any ideas on what is causing this would be greatly appreciated. It is
driving, no pun intended, nuts.