can't maintain constant RPM

[harry444]

Hi all i have a G1 90 laser nt when I drive on the highway at a constant speed my RPM's flucuate up 300 rpm and back down almost like trans slipping except if i excelerate it goes away I thought it was o2 sensor was getting cel so put in a new O2 sensor engine runs alot better except didn't cure my original problem. plugs are new wires check ok pvc valve changed any ideas thanks

 

[NOSNUSE]

At what speed do you drive on the highway, it sounds to me like your torque convertor is jumping between lock-up and nonlock-up of course you should check your trans fluid and make sure that you change it and the filter about every 15k to 20k miles. It may just be your filter is clogged and not getting enough fluid through the trans to keep up the pressure that the trans needs.

 

[harry444]

It seems to be around 65 and 70 mph it doesn't do it all the time seems to be intermitent its driving me crazy car shifts normal holds on hill btw changed trans fluid and filter about 12000 miles ago it also did it before I changed fluid it is driving me nuts !

 

[samuraitekno]

any update on this? my trans is doing the exact same thing. it is very annoying.