Lately, my 1994 Vision 3.3L seems to studder around 60 km/h (40 mph)....it seems to occur on inclined roads (but sometimes on flat roads as well) and when i slow down then try to accelerate. The studdering usually stops when going at constant speed or when i eventually reach 100 km/h (60 mph). At highway speeds, the car runs fine. How do i diagnose whether its a tranny or engine issue? Thanks
The 40 mph shudder might be transmission related. Try this:
On a controlled test drive, see if you can find a long gradual hill. One that will allow you all upshifts without much accelerator effort. Once you hit 4th gear try to give a little bit more acceleration past 45 mph, then let off and coast down to 40. Accelerate lightly, If the shudder starts and kind of hangs around up past 45, I'd almost bet the Torque Converter Clutch is at the end of life.
ok....did more trials...........from a dead start and hard acceleration..the car doesnt studders...even when going up an incline......seems to always studder when i take my foot off the accelerator pedal, let the car slow down and then i accelerate again.....its during this acceleration phase that the car studders/hesistates......this happens on flat, uphill or downhill......im not sure how plugs would cause this symptom.
On the 1G 4th gear lockup is after exactly 40mph. Most seem to think its a phamton 5th gear.
I am going to go with either motor mounts or CV axles. To test for mounts need to have some one hold the brakes hard, and with the motor in gear (drive then reverse) rev it a bit and see how much the engine moves. A bad trans mount can create a 1 inch sag on the rear and the motor mounts even more.
These cars shudder when accelerating if the drivetrain is not aligned perfectly. Mine shudders ever since I lowered it because of the axle angles, however it has just proven to be an annoyance issue rather anything else.
Edit: Just read where you say hesitates, old plugs/wires can cause this issue. Make sure to run Champions plugs at all times, or NGK V power (have used G Power before with no issues)
Update: Took the advice of installing new Champion plugs and wires....it fixed the shuddering....i would never thought an electrical issue could cause that symptom.....so glad my tranny gets to live another day....thanks