93 3.4 fast Idle need help?

[white96six]

Hello my wifes 93 3.4 started Ideling fast 1500 rpm. so I replaced the Idle air control valve and it fixed the problem for about a day but now it is Idleing fast again. any suggestions? thanks in advance.

[cero]

mabey brake booster

[viper98885]

Have you tried disconnecting the battery for a few minutes?

It could also be a vacuum leak. The vacuum hoses on the 3.4 are at the MAP sensor(rear-passenger side of upper intake manifold), the EVAP sensor (mid-driver's side of upper intake, the fuel pressure regulator, Power brake booster and then there is a junction right next to the fuel pressure regulator and on the back of the upper intake manifold.

Also, the large fitting near the front of the y-plenum has a rubber boot that tends to deteriorate. Check the condition of that seal.

Otherwise, check out the condition of the vacuum hoses that are mentioned above and listed for any hissing under the hood.

[white96six]

thanks for the replies. I have disconnected the battery and it quits doing it for a day and then it does this again. would it get better if it was a vacuum leak? I think it might have to do with the brakes becuase sometimes when you push on the brakes it goes down a few hundred RPM for a second. how do I check the brake booster? thanks.

[viper98885]

It is normal for the idle to drop some when you press the brakes because it is using the vacuum from the engine to assist the braking.

[InZane4all]

Hello.
My car was doing this for quite sometime and got really annoying. People told me to change the AIC Valve, and did. RPM's went back to normal for a while, and then it would start ideling at 1500 RPM's again. I ended up switching the AIC Valve about 6 times, but no dice, problem kept coming back. Anyway, I recen't had to get my EGR Valve replaced. Turns out after I got that fixed, car hasn't done that since. I don't know if the EGR Valve and the car ideling at 1500 RPM's have anything in common as far as RPM's ar concerned, but it worked for me. Hope this helps. [img]graemlins/dunce.gif[/img]

[94bird]

I've had the same problem with my 3.4.
Replaced the IAC, reset the computer, checked vacuum lines, it still idles high once in a while but eventually it goes back to normal.
I can't figure it out, so I've just learned to live with it.