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Discussion Starter #1
Well, after replacing MAF, plugs and wires and pretty much ruling out driveline vibration, I'm back to the engine looking for the source of vibration. It has to be either ignition or fuel delivery to a cylinder.

I'll be hooking up a timing light to each wire to ensure there's juice to all the plugs.

But anyway...here's the symptoms.

Sporadic rough idle - almost feels like a miss.
Droning vibration at highway speed. Almost like bad Ujoints, but I think it's because I'm not consistently firing on all 8.

I can check the ignition stuff. How can I test an injector? Would any sensors be causing this?
 

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Youre probably experiencing a couple different probs;First, the vibration under way most probably is due the notorious 2 piece drive shaft which , after changeing rear gears, or just applying too much tork a few times starts to deflect into an out of balance condition under load at speed... It will drive you nuts , and mess up a tailshaft bushing in a hurry, thus a high percent of long term TCCoA members have a 1 piece aluminum Driveshaft ... do a search... The sporadic miss is another story; what comes to mind is a bad 02 sensor, or water in the fuel, and then the evil old MAF about ready to go, or possibly the new wires... they are a tiger to get seated on the plugs sometimes, and even then. unless they are ford pieces, or the really high quality aftermarket stuff, theyre still suspect. There are other things , and I am sure there will be more advice forth coming. good luck.
 

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Discussion Starter #3 (Edited)
The new MAF, and wires are OEM stuff right from the Ford dealer. The DS was out when I had the tranny done and the vibration really started in earnest after I got the car back, but I can't tell if the miss in the engine is causing the vibe, or the DS itself.

I took it back to the tranny place and they ran it up on the hoist. Ujoints are still good and tight...I know that wouldn't indicate an out of balance condition.

That thing is a MONSTER to get out of there though! Who the F#%& thought it would be a good idea to route a DS over the gas tank anyways? Looks like the exhaust would have to be unbolted, the diff released, O2 sensors disconnected....everything just to get at the DS. Am I right?



Damn car is turning into a money pit fast.
 

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Desert Rat said:
Damn car is turning into a money pit fast.
:D Welcome to da club Bro! :D
The best bet is a used 1 piece shaft outa a
MK- VIII, but I am not sure which are best.... do a search... the so-called metal matrix Driveshafts that Reinhart used to hawk as his are actually a Dyno Tech aluminum shaft which can be had cheaper direct than from jobbers , no matter what they call them than from a jobber..... best bet is a salvage yard , or someone selling one here....
The miss can be so many things, and a first step would be to dump a can of Berrymans B-12 in your tank to clean up the fuel system/injectors ... after a tankfull if its better... thats your answer... Maybe by then the sucker will throw a code.... does it idle better in gear with the A/C on ? or with A/C off? if better with A/C on, you are leaning towards upstream 02 sensors, and if so use Genuine ford only (Dan Newman's the man for those)... there are more things but those are a few to chew on... BTW, Pulling the shaft and spinning it to check the balance reveals nothing as the thing actually deflects under load to cause the imbalance.(cause its a two piece unit , one of Fords better Ideas).. no load and you can spin smoothly all day long, go figure.... good luck
 

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Discussion Starter #5
So does it have a carrier bearing hiding above the tank for the 2 piece unit? If it does, i assume that comes out to fit the one piece unit in there....

I've had air injection done on the fuel system about 3 tanks ago and ran some good deposit remover through it. Unless an injector is dead, I'm leaning towards ignition as the culprit, despite all the new parts there. It's been 115 degrees outside when I get home from work this week, and tinkering on a hot motor in those temps has made me procrastinate checking the plug connections....

Back to the DS...getting one out of a yard kinda scares me. Is the part still available from Ford?
 

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Desert Rat said:
So does it have a carrier bearing hiding above the tank for the 2 piece unit? If it does, i assume that comes out to fit the one piece unit in there....Back to the DS...getting one out of a yard kinda scares me. Is the part still available from Ford?
well, there is no carrier per see, hidden above the tank, but what you have is some swaging up there which is all holding the inner shaft in place on the outer shaft..... You see, that way ford could slip the thing together at different lengths, and and have different length shafts coming from one assembly line as the need arose. Its the teeny bit of slop on the slip fit and the swagging causing an internal deflection under load that causes the vibration .... Its maddening, but a fact of life... As I said before, do a search , tons of info on it.... Fords prices scare me more than a salvage yard, go figure, and I am not sure whats available from Ford these days...good luck!
 
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