Idle problem (still)

[Mystery Train]

Problem: When I put my '98 in park, about 40-50% of the time, it steadily climbs from about 900rpm up to 3000, where it holds. It won't go back down unless I put it in drive or reverse for a few seconds and then back into park. Even then, sometimes it will still rise back to 3000. Noticed that it is a bit more frequent when the car has been driven a while. Not as frequent if the car hasn't been running long. OK, I've read plenty here about the idle air control valve. So, I took the car in for some brake work, tranny & ps fluid flushing, and decided what the heck, get the IAC replaced. 190 bucks. Everything fine for the first day. Wife reports problem on second day. Today, problem is back in full.

I'm going to take it back to the shop, but I want to give this guy some clue as to what it might be. If it was the TPS, I'm told I'd experience the problem during other situations other than park. If it was a coil pack, wouldn't I experience a "rough" idle or missing? That's what I've read here. I'm no mechanic (though ford is intent on making me one ) but I can imagine some sort of electronic glitch, loose/dirty connection. Something that would account for a sporadic problem as I experience.

Please help!

Thanks,
MT

 

[Petersho1]

TP connector, get new one "updated"
v8sho.com/sho/highidle.html

 

[93SHO'nOFF]

I agree with Petersho,hear is a copy of TSB to get #

FORD: 1998-99 TAURUS SHO
ISSUE:
A high idle may occur on some vehicles. This may be caused by a poor electrical connection at the wire harness to Throttle Position Sensor (TPS).
SERVICE PROCEDURE
Verify the concern vehicle exhibits a "high idle" condition when shifting into Park or Neutral for Taurus SHO. If high idle condition is not exhibited, proceed with other driveability diagnostic fix procedures. If condition is present, obtain a High Idle Service Kit (XF1Z-15K607-AA) and proceed by following the instructions found within the service kit.

PART NUMBER
XF1Z-15K607-AA/ High Idle Service Kit

 

[99V8SHO]

I have experienced this problem once, about 3 months ago, but it has not happened since. If you do keep experiencing this problem, I would not recommend dropping it into gear to bring the revs down, I am sure that is **** on your TC. I would just shut the car off, wait a few seconds, then start it back up.

 

[spragers]

I had this same problem three times this summer, always after long (50+ mile) drives. I had my mechanic put the new wiring harness in, they also found that some other shop had already tried to fix it, but they had stretched the wiring so badly that the insulation had cracked, peeled, and the wires were nearly broken through in spots. No wonder I was having problems

It shouldn't bee too difficult, or expensive, to fix, depending on which route you go.

 

[Mystery Train]

Thanks guys. I'm going to take her in this week along with a printout of the above. I'll post the results.

MT