1994 FJZ studder around 40 MPH - help! (1 Viewer)

[sflafjz80]

Hello all.

Need help here.
I’ve got a 94 triple locked FJZ with 274K. I’ve been working on her for a few years getting her back to fighting shape.

Current issue is around 40MPH (really 30-40) when I am slightly pushing the gas peddle on and off it seems like the car will start to studder / jolt. If I add more gas it stops. I’ve tried with OD on and off same issue. It seems to be related to the gear it is in?

Anyone seen this? It’s difficult to explain and I can try to post a video.
Transmission was serviced 10K mikes ago.

 

[12bit]

Are you getting a CEL when this happens? Any codes?

 

[Malleus]

What excatly is shuddering? The engine, the front end, the suspension, the whole drivetrain...?

 

[sflafjz80]

No codes or lights.
The Tachometer jumps and it feels Ike the transmission slips/ the truck does a mini “jolt” It’s only when I’m around 30-40MPH cruising steady with little gas. Add more gas/ acceleration and it goes away.

 

[lp2k]

grease the U-joints - has something similar happen to me

 

[gummycarbs]

The Tachometer jumps

How much? That doesn't sound good.

 

[sflafjz80]

To follow up-- the issue was the distributor. A rat (or other rodent) chewed a few of the coil cables.. Engine was mis-firing.