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94 GT destined to shake forever.

2K views 13 replies 5 participants last post by  scottydsntknow 
#1 ·
Hello, guys. I've got a 94 GT manual with a terrible shaking issue.
The easiest way I could explain it is if one plug is missing or something causing a stumble.
There isn't really a rhythm to the shaking, but sometimes the car will shake like it's stupid built.
I've got a vacuum gauge hooked up, sits at 15 pretty decently but drops to 13 when it starts to shake bad.

Anyways, I've got a long list of parts I've replaced and still haven't figured it out.
Also, mechanic said my mounts look good. No engine codes at all.

New EGR
New TPS
New IAC
New AIT
New MAF
New PVS
New FPR
MotorCraft Fuel Filter
New PCV
Bosch O2 Sensors

Mac O\R H Pipe
AutoCraft Spark Plugs
Frpp Spark Plug Wires
Msd Cap and Rotor

AutoCraft Silver Battery
New Harmonic Balancer
New Alternator
SR Smog Pump Delete

Also, I've been through vacuum lines a ton, only lines I haven't checked are in the cab and under driver side fender.

What gives?
 
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#2 ·
I just went through the same type of thing. I put a new trans in my 95GT and it had a miss that wasn't there before. I replaced all the same things, plus some. Took it to a dealer to diagnose. They found a fuel injector unplugged. I never thought to check that. Fixed the problem and it runs like new

Jim
 
#4 ·
Could be a plug wire that is grounding out some where causing the misfire. Personally I will not run motorcraft plugs, ive had to many sets where I end up with one that is bad from the factory. Switched to NGK's and have not had a problem yet.
 
#6 ·
On my 95' F150 5.0 I had an issue where I was swapping plugs and wires. One of the wires on the passenger side got nicked on the heat shield around the header, that little tiny nick was enough to cause a random misfire every time the wire bumped into anything near it. Took weeks to find that one and it was by pure chance that I caught it at all
 
#7 · (Edited)
#9 ·
mine did something like this shaking really bad, it was harmonic balancer, but I see you already changed yours
 
#10 ·
Might be the flywheel or clutch then. Or the driveshaft could be completely screwed. Did you try to work the clutch to see if its a driveline issue or not?
 
#12 ·
I had a 91 that shook like a mofo. Turned out the clutch was ****ed and a new clutch fixed it right up. Make sure you do the flywheel too while you are at it. I think standard flywheel is selling flywheels cheap on Amazon right now. You could also take your DS to a shop to get checked too while you are at it if you want. Its cheap to have them checked.
 
#13 ·
just curious, but check the driveshaft for what?
 
#14 ·
Check it to make sure its properly balanced. Or he could just upgrade to an aluminum while the trans is out for the clutch.
 
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