Outta nowhere the idle hangs at 1700 or so?

[Fairlaniac]

I changed the IAC and TPS but still have on occasion the idle will hang at 1700 or so. If I drive local it doesn't seem to happen. When I hit the highway and hang about 65-70 when I get off the ramp it is hanging. The next few miles of local roads it still hangs high until I shut it off.

The only code I get is 41 (EGO sensor?) and 67 (improper signals). Any ideas?

Also each day when I drive after about 20 minutes driving the "Check Engine" light comes on. Again when I get off the highway to slower speeds it will go out.

'91 2.9/5 spd. 4x4

Thanks,

 

[sjr53]

Maybe a vacuum leak in the brake booster. If possible pull over and unplug the IAC valve wiring & see if the idle stays up from a vacuum leak or drops low or kills with no vacuum leak.

 

[Fairlaniac]

Re:

When I pull the IAC the engine dies immediately