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Discussion Starter #1
Again another misfiring question. My local parts store supplied me Autolite 766 spark plugs. They look totally different to the mixed bag of plugs that I took out. Namely the thread on the mixed bag ones are twice the length. Are 766's one of the many types that can be fitted to a 95 4.6 T.Bird ?
 

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I've never used that plug.

The plugs to get are the double platinum plugs, APP104, IIRC.

They're the same as the stock plugs, with platinum wear surfaces on both sides.

Copper plugs only last 10k miles before problems; double platinum will go 100k miles without problems.
 

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Wonder what led them to sell you 766 when the book says 764. My first choice on my 95 LX 4.6 is Motorcraft. I'd at least go with the Motorcraft SP493 if not the APP104. BTW, in my experience if it's misfiring, more likely plug wires than plugs.
 

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My results are a little different - I got 30k miles out of coppers, but only 60k or so out of the platinum's. The original platinum's on my current MN12 were well worn looking at 64k. A new set gave it noticeably more pep.

For some reason, I am remembering using Autolite 103's in my old T-Bird, which is one step colder. But I may not be remembering correctly.

Al
 

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Discussion Starter #5
Ive already done leads and coil packs. Im hoping some different sparks than the ones supplied by the parts store will help cure the problem. Ive cleaned the usual suspects and now have two tins of Seafoam at the ready !!
 

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Discussion Starter #6
Right folks changed the plugs ( again ) leads and coils changed. New battery, seafoam in the fuel tank. Seafoam down the throttle housing. The bird idles smooth, however, any pressure on the gas pedal it misfires... backfires the works!!!! Total loss of power. Any ideas ???
Thanks
 

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Could that be a limp mode the computer is in? Disconnecting the battery for a while will reset a lot of computer codes.
 

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First of all, if the replacement coils are aftermarket, put your originals back. The factory coil packs literally never go bad on these cars, but aftermarket ones frequently do, so put the originals back to rule that out. If the misfire is still present, I would look for a vacuum leak.
 

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maybe you can get a volt-o-meter and check the resistance on ur coils or plugs or wires. whichever one goes thru check the resistance and make sure the cables still work. that would be my process before buying a bunch of parts
 

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What did the old plugs look like when you removed them ( did you keep them in the cylinder order ? ) .. anything out of the ordinary, excessive gap / buildup, discoloration, black / white ??? That might tell you if one cylinder in particular is giving you an issue to help narrow it down.

Also if its a pair that is shared on a coil that might point you in the direction of a bad coil - then you might need to check if the DIS module / EEC is firing. Otherwise, Fuel injectors is another possibility .. hopefully you saved the old plugs in order to help diagnose your issue.
 

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Discussion Starter #14
The plugs were in the car for a good few years. From what I can gather the Tbird was a airmans at RAF Mildenhall and when he returned to the US he left it behind. It stood for a good few years at a garage. This was until the gent i bought it off had it. His intention was to put the engine and gearbox into a limo. However, he changed his mind and tried to get the bird back on the road when he gave up and I took over.
 

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If it sat a long time, then your misfiring symptom is probably from old gas. A can of Seafoam and fill 'er up, if you haven't already.

Al
 

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Discussion Starter #16
Well I started from the beginning.....found that the gent I bought the Bird from had badly cut the rear floor pan to fit the new pump. The fuel gauge is faulty.... its showing full and found the tank to be empty. Checked the fuel lines and found a rusty dented fuel filter with petrol in it that I can describe as un hydrated urine in it. I'm hoping with a new filter seafoam and some fresh fuel the issues might abate.
 
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