HELP, Can find out why it's missing

I am new to this site but I have found it extremely interesting. It appears that even the meekest member knows more about Turbo Coupes than any Ford Dealer!
I have a 87 that has a bad miss. At an idle, it will miss about once every few seconds.If you have a timing light on it it will kill the light for a moment and the timeing will change approxmately 10 degrees. sometimes advance the timing sometime retard the timing. I looked for vacuum leaks but found none.I have replaced the spark plug wires, cap, coil and plugs with good ones not PeP Boys brand, I have replaced the distributor components with new parts and finally disconnected the altenator in case it was giving feed back to the computer. All changes seem to help a little but the miss continues. It is really pronouced when you are between 3500 and 4500 RPMs. I do not know how to test the computer but feel that is my last guess. Do you know where I can get one and what would be a good price. Out here in California you can send yours out to NAPA auto Parts and in 8 weeks it will come back fixed maybe!

You might not want to hear this, since you just did a tune up, but only use Motorcraft parts for everything: cap, rotor, plugs and plug wires, PIP generator (Hall effect sensor inside dist) and TFI. I think all of us have had problems with other brand stuff, even "premium" brands, like Bosch. The 3500 to 4500 RPM miss often seems to be related to plug wires or plugs.

Also, run the codes, and look for any continuous codes. Check the connector on the TFI module to be sure the pins are clean and not getting pushed out of place when you put the connector on. Check the SPOUT connector to be sure it is making good contact.

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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 // 00 Windstar (wifes vehicle)

Ive never had trouble with my aftermarket plugs, wires and cap, rotar that are all non Ford Motorcraft items. I would now look to spark plug gap and fuel. Replace your $10.00 fuel filter and test your fuel pressure. I would also add a bottle fuel system cleaner in the gas tank. Try those and contact me back.

what do you guys running 18psi run your plug gap at? and I run accel 8mm and they run great, have on all my fords... but what about plat. plugs? can you run those?

Originally posted by methos:
what do you guys running 18psi run your plug gap at? and I run accel 8mm and they run great, have on all my fords... but what about plat. plugs? can you run those?

I saw a theory around here about a month ago, where someone suggested that the platinums have a different resistance, and it was confusing the TFI.
I got bosch plats before I heard that,with motorcraft everywhere else, and mine has a slight occasional miss across the board. As well as a big miss at idle - engine actually cuts out for a split second - but not all the time. any missing usually only appears after the car is warmed up good. More noticeable after a hard run around town. I'm assuming that the inc. heat causes inc. resistance further confusing my tfi....

check for a cracked plug

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Jerry Rutten
88'Turbocoupe

Assuming the tune up is good I would look into the distributor. The hall effect sensor and PIP. I agree with using Motorcraft parts. They work on some bitchin turbos without problems.

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85 TC 5 speed, K&N filter charger, Ranger Roller cam, 3" exhaust system, manual boost valve, large VAM, SVO PE computer, front mount intercooler, underdrive pulley, ported upper and lower intakes, 245/45/17 wheels & Tires