91 3.0 V6 4WD Engine Fluctuation

[calpolywally]

My '91 3.0L V6 has been fluctuating RPM's just before shifting from 2nd to 3rd. It'll rev up to about 3400 rpm then drop to about 3100 rpm, then wind back up to about 3800 rpm and shift, all with the same pressure on the gas pedal. Any thoughts?

Also, does anyone else have issues with the tranny constantly downshifting on the freeway with the cruise control on? Is this a sign of a problem or just the lack of power in the engine? Thanks!

 

[Geolander]

My '91 3.0L V6 has been fluctuating RPM's just before shifting from 2nd to 3rd. It'll rev up to about 3400 rpm then drop to about 3100 rpm, then wind back up to about 3800 rpm and shift, all with the same pressure on the gas pedal. Any thoughts?

Also, does anyone else have issues with the tranny constantly downshifting on the freeway with the cruise control on? Is this a sign of a problem or just the lack of power in the engine? Thanks!

I assume this is with the auto?

No idea on the fluctuating revs before shifting, but the downshifting while in cruise is probably a combination of not-so-great transmission and lack of power. I've driven cars that do this before. It could be that you're running close to the transmission's set shifting rpm, so a small fluctuation in rpm will cause it to shift, or it could just be that you're going over hills and the engine is struggling to power you up them in the higher gear.