Very high Idle 99 Passport

[RobF]

My 99 Passport had idle problems. I was told to replace IAC valve, but when I replaced it, veh. now idles around 4000 RPM! Can't seem to get it down, except by unplugging IAC, pulling plunger out and reinstalling it, but leaving it unplugged. When I do this, it idles low, but surges up and down between 500-1200 RPM. Help! Anyone have any ideas?

[amigo-2k]

most likely the intake manifold gasket. a very common problem.

see the FAQ's for more info.

[RobF]

Originally Posted by amigo-2k

most likely the intake manifold gasket. a very common problem.

see the FAQ's for more info.

Ok,
I replaced the IAC valve, and the PCV. Engine idles at 2000- 2500 RPMS steady, with no surging. CEL says P0507. Is it possible I got a bad IAC? Any way to test this to see if it is working? Do you think this still could be the IMG?

[marcre]

I would definately check the IMG. To me at least, it seems like everyone has similar problems when they go bad, but there are also differences as well. Whenever there is a problem like you are experiencing it is good to check the IMG first, since it is a known issue. Your idle issue is what leads me to believe this is your problem.

When my IMG went bad the codes were pointing me in all sorts of directions. After spending several hundred dollars in repairs, I looked at the IMG. That was the culprit. The Rodeo has been running smooth ever since. I just wish it didn't like drinking oil on occasion.

Marc

[RobF]

Thanks Marc-
Do you know of any specific tests I can perform (resistance, voltage checks, etc.)? I just spent $60 on a new one from dealer and want to make sure it is working. I thought it was odd when I unpackaged it, removed the clip holding the pintle in, and it did not spring out. Not sure if it was supposed to, but assumed so because of the spring clip.

[RobF]

Originally Posted by RobF

Thanks Marc-
Do you know of any specific tests I can perform (resistance, voltage checks, etc.)? I just spent $60 on a new one from dealer and want to make sure it is working. I thought it was odd when I unpackaged it, removed the clip holding the pintle in, and it did not spring out. Not sure if it was supposed to, but assumed so because of the spring clip.

Oops... I thought you said IAC I am going to try the carb/ brake cleaner test tonight on the IMG.

Thanks!

[marcre]

It is possible you got a bad IAC, but I am not sure how to test it. Remember though, with the IMG and the carb cleaner test, it is not guaranteed to work. It may not, but I suspect with the problems you are having it will.

Hopefully someone else will chime in about the IAC.

I am not an expert when it comes to auto repair, but my IMG gave me so many problems, I feel I know them inside out.

Marc