Idle problem only when cold

Hi i have an 87 t bird. My problem is a wierd one. Anythime the car su=its overnight or for awhile enough to cool down i have an erratic idle problem. The problem will start after the car has been on for a few seconds. The idle will jump up and down from 500 to 1500 and sometimes stall. The other problem that occurs at this time is if i try to hold the rpms to say 3 grand it sputters through the rpms like its missing. After about two minutes the problem totally disappears and the car drives great. I can rev it to 5 grand no problems. I am stumped.
to date here are things that have been changedto fix this problem
1) new vam meter
2) new coil
3) plugs and wires, cap and rotor
4) IAC
5)Computer
6) tfi module and pickup
I dont understand how it comes when the car is cold then leaves completely.Any advice would be greatly appreciated

With the engine warmeds up, pull the codes.

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NATO Member. it's not a vice, it's an obsession
Good judgement comes from bad experience, and a lot of that comes from bad judgment.
88 TC X 2, 86 SVO, mods list at
http://www.turbotbird.com/showroom/pd_88tc.htm

i suffered through this problem 2 years ago,
i finally changed my TFI and PIP with FORD MOTORCRAFT parts and it has never come back, i stil have the module and i put it in my parts car and started the car up and it did it, so its that bad module,
its a common thing with this. i thought my car was cursed for a while, try another moduel but make sure its a ford part. brnad new not remanufactured.
these TC's are sensitive and need Ford parts for igniton or EEC-IV computer related stuff to be Ford

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Brian J Larkin AKA Turbo
1988 Turbo Coupe 5spd
Twilight Blue
boost valve, k&n cone, glasspacks gettto rigged ram air, cracked header panel
[Image: burnout3-9.jpg]

[This message has been edited by BJL (edited 04-22-2003).]

How much does a new TFI and PIP cost all together by the way? All this talk about needing one makes me curious....

I have used motorcraft parts and they are new not remanufactured. That is why i do not understand this problem. As long as the car is warmed up the problem will not occur. Anyone think it might be the engine temp sensor? I appreciate any ideas this is really annoying me. Thanks guys!

I am thinking ECT problems. With the motor cold, pull the connector off the ECT and measure its resistance. With coolant at 50 deg, resistance should be about 58,000 ohms. If it is significantly lower than this, replace the ECT.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)

My original TFI caused a bad miss at ~3000 RPM. I replaced it with a non-Motorcraft TFI, which caused the exact same problem as you're experiencing. Put a new Motorcraft in, it wouldn't advance the timing (very sluggish until 3000 rpm) and then died the next day. Got another one, and it's been good for the past year. I'm kind of leaning toward the ECT, but don't totally discount the TFI just because it's new.

Well i just got done replacing the ECT. It isnt the problem. I put a brand new one in and it is the same problem as before. Im gonna go and try to buy a new motorcraft tfi module. I cant see it being anything else. Im open to suggestions but tommorow i will be buying the tfi and tryin that out. Thanks guys

If you like spending money and not fixing the problem then please don't:

With the engine warmeds up, pull the codes.

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NATO Member. it's not a vice, it's an obsession
Good judgement comes from bad experience, and a lot of that comes from bad judgment.
88 TC X 2, 86 SVO, mods list at
http://www.turbotbird.com/showroom/pd_88tc.htm

Well i ran the codes today at my mechanics shop. We got a code 81 after the car was warmed up. It said something about a thermactor or bypass check circuit. I dont have a clue what this is or where the thermactor is. anybody with any info id appreciate. Thanks