Hi guys my 89 is doing something very weird when I’m applying throttle and it gets past 3rd gear the rpms fluctuate while cruising almost like it’s up shifting and down shifting over and over
anything helps thanks
also I have a video but it’s not posting on here

 

Does it feel like its shifting, or is it just the RPMs moving around without shifting?

 

Sounds like it could be the torque converter locking and unlocking. Have you checked the condition of your transmission fluid? Has it ever been changed?
Don't go running down to the local "lube" shop for a transmission drain and refill either that could cause you severe problems. Search the site for correct method.
I was having a problem with torque converter locking up and cured it by cleaning the ground connectors and cleaning the connector going to the shift solenoids.
I am not sure that is applicable on a 89, however.

Good Luck!

 

Yup.......

 

If you don't get any clunking or so... I'm thinking it's the overdrive comming on and off?
I don't know how you would check that.

 

yes it feels like it’s shifting

 

no clunking

 

fluid was changed a month ago no problems until now I did replace the tps and adjusted it with the square connector

 

It actually does this in every gear

 

Yep. Tips 1 and 10 at www.cruiser54.com.

 

Is it on decel where the tach needle goes up and down in RPM in a cycle?