94 gt 5.0 aode swapped to T5

94gtlazer

New Member
Feb 15, 2021
2
0
1
37
Conway AR
So I bought a 94 gt 5.0 that has a 5 speed trans. Since I bought it it's always had this miss or bucking when cruising at highway speeds. I have the obd1 scanner for it and ran codes and I got 637, 654, 621, 622, 652, 624. All of which are for an aode trans. My question is is there a way to wire or bypass pins in my ecu to make it not try controlling the trans or shift timing?
 
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NXcoupe

Active Member
Dec 3, 2009
75
27
28
Dayton, OH
Short answer, no. You need a manual computer or a chip that turns off all the auto functions. Getting a T4M0 computer is cheaper and easier.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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^ WHat he said

The correct way to do the trans swaps includes changing a few bits of wiring and the ECU.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
36,933
12,800
224
Massachusetts
Unknown. It could be arcing wires, or bad spark plugs, or other misfire or fuel related issues. You’ll need to start troublshooting starting with a possible misfire under load
 

jozsefsz

5 Year Member
Aug 11, 2013
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Cleveland OH Area
It shouldn't cause a miss or buck at highway speeds, it will typically cause a bit of hesitation when it reaches the automatic-trans shift-points (due to the timing getting retarded). But at cruise it's likely not the transmission / computer setup. More likely a lean condition - as Mustang5L5 suggests a fuel related issue. Could be O2's, MAF, fuel pressure (pump or regulator or filter - easy enough to test with a gauge). Vacuum leaks or other sources of un-metered air (like the PCV system - especially take note if you have a cold-air-intake). A full tune-up is advisable - plugs, wires, cap & rotor, O2's if they've never been changed, clean MAF, change fuel filter, check fuel pressure. Listing any mods would be helpful too - if everything's in good shape it could be the car was modified but never properly tuned.