My 01 Navigator with 183k miles has an issue with "almost" stalling. After heavy braking then immediately pressing the accelerator, the tach will sometimes drop to 200 or 300 then back up above 1k and runs fine. For example, traveling at 55 to 60 mph, start braking to make a 90 degree right turn. Let off the brakes and press the accelerator while turning and the near stall occurs. I can almost predict when it will happen. Already replaced the IAC and getting ready to replace the vacuum rubber connectors. I'm thinking vacuum leak. Suggestions or ideas? And I'm sure this has been thoroughly discussed, didn't have time to find the other post.