PLEASE HELP 95 Cierra 3.1 lt. High Idle (always)

[chiefdlane]

HELP,

I am new user here at the forum and would appreciate any help possible.

Our 95 Olds has developed an extremely high idle, I mean it's screaming, it would slow down after 15-20 minutes of driving, but now does not.

I changed the Idle Air Control Valve yesterday and it did not help. Before I start replacing parts does anyone have any thougts?

I know this probably applies to at least a decade of various GM vehicles but figured I'd start here.

Thanks

[jsgold]

Normally I would think a MAJOR vacuum leak, as it cause this, IAC(which you replaced), or, possibly the TPS (throttle position switch). It can be tested with a scan tool. Any check engine lights??? Did you unhook the battery when replacing the IAC? Start looking for broken or loose vaccum lines. Check all of them. If your heater controls are acting screwy by chance, check there too.

[chiefdlane]

Thanks JS,

I did NOT disconnect the battery. I just bit the bullet and ordered a diagnostic scanner, getting tired at guessing. Hopefully that will pinpoint it.

Once in a while the "Service Engine Soon" light will come on but not always. I did check for vacuum leaks and did not find nor hear any.

I really appreciate the help,

Dan

[GTP Dad]

Are you getting any water in the oil? This sounds like there may be a leak in the intake manifold gasket. The TPS could be the cause if it is totally out of wack like jsgold stated.

Welcome to AF!!!