start up idle and throttle body

[hans747]

I know we are talking apples and oranges here, but last night I had the same exact problem with my Lincoln Mark VII. It idled like crap when the AC was on (jumping between 800 and 1200 rpm, I know it doesn't sound like much, but that's enough RPM to make you start rolling away at a stop light with that 5.0 engine). I asked around the Lincoln boards, and everyone told me to remove the IAC and clean it out. the thing was completely gummed up, and that prevented it from opening and closing fast enough to accomodate the extra strain of an AC system. I cleaned it out with trottle body cleaner, and my idle is a lot less irradic now. Give it a try. Also, that EFi relay seems to be a big one.

Eric

 

[MoJ]

"By process of elimination it is pretty clear that it is not the act of cleaning the chamber, butterfly or intake plenum since people who have done that have not always experienced results and people (well actually me) have also experienced results without doing it."

Agreed -- - - For me, cleaning it fixed the warm LOW-idle problems I was having - been months now with no return. It did absolutely nothing for the high start up idle problem that makes me grit my teeth every time I start it cold.