Contour Enthusiasts Group Archives Forums General Troubleshooting TH fix trouble

So, two weeks after finally, with the indispensable assistance of Montreal's own blacknblue, applying the TH fix to my car, I have a problem.

Car was great until Friday afternoon, after a long, high-speed run down the highway. (85 MPH for a hundred or so miles)

At the first pee break, the car idles down to about 1500, then jumps to 2000 or so, sticks there for maybe four or five seconds, then settles in at 14 or 1500 RPMs. Has been that way ever since...won't idle below about 1400.

Until just now, when I removed the TH plug, and everything's back to "normal", throttle hang, but a nice 750RPM at idle.

Any ideas?

I thought I was the only one.....
After the TH fix my 98 E0 SVT drove great for about 5 miles..... When I first installed the end cap, i started the car and went through turning on every possible accessory (AC, Rear Def, High Beams, stereo, windows, etc....) to make sure the engine would not stall when idleing. NOW, when i drive the car it has eliminated the hang from higher RPMs but the car will not Idle down from 2000 or so for about 10 seconds after I have released the accelerator and it only Idles down to about 1300 or so.......

I'm in the process of resetting the computer to see if that helps....
any advice???

Jason

I think resetting the computer would definitely help. Also what size are you using? 3/16" was giving me stalling problems but 7/32" was perfect.

i agree. i have problems now and then with the car idling too high, exactly as you describe. the computer likes it if you reset it every once and a while. that will temporarily fix the problem. i suspect though that the real problem is coming from a faulty iac valve. i know that mine sticks now and then and when it does my idle drops to 1100 or so then pops up to ~2100 and stays there. if i throttle it real good while driving it usually fixes it for a little bit. i've had my th cap installed for a good 9 months now and no problems until recently. soon i'll order the new iac and install it. its only like a $35 part and takes about 10 minutes to install.

I have a 3/16" hole in my plug. There were never any signs of stalling, not so much as a stumble, even with full accessory load. As I say, it worked great for about two weeks of driving around town, but the first high-speed trek seemed to screw it up.

I don't think it's the IAC valve...mine had been sticking, and I had it replaced by the dealer about a week before the TH plug went in.

I'm going to put the plug back in a couple of days (when it stops raining) and reset the computer at the same time.

We'll see.

dont be surprised if its bad again. mine didnt make it a year after the dealer replaced it the first time.

Well, I put the TH plug back in this morning, and reset the computer at the same time (unhooked the negative battery cable while I was doing the TH fix, then hooked it back up when I was done...that should be long enough).

So far, so good. At a stop, the RPMs drop to about 1100, sit there for a second, then gradually fall to 750.

I hope "the fix" lasts this time: Shifting gears is much smoother this way!

Today I did the TH fix for my 95 SE; followed the FAQ. I'm a little worried that the hole in the copper pipe cap isn't 'clean' enough and may be too big. I used a 15/64" drill bit but couldn't get it to turn smoothly through the copper cap. The result is some sharp shards along the outside of the hole. I filed them down a bit, but I'm wondering if there's danger of little flakes of metal falling off and getting into places they don't belong.

Any thoughts?

The throttle hang does seem to be much less noticeable now, although I was more concerned with eliminating the moose. I won't be able to tell if the moose is gone until the weather warms up a bit; my moose is always AWOL in cool weather.

Well I took the car to the dealer and apparently my IAC valve went south about the same time i did the TH fix. I threw a CEL a day or so before i did the TH fix, but no obvious drivability problems........
Then I began driving like normal and suddenly the car has a sticking hang at about 2000 RPM (described above)

Does anybody know if replacing an IAC valve is a job that is possible for the home mechanic?

Thanks!
Jason

IAC is a half hour job at most and the part goes for ~$40. it's not a difficult repair. ford will charge ~$150 to do it.