Lower than normal engine RPMs at speed

[PerfectAgent007]

Hey everyone. I've got a 2007 4Runner V8 with just under 160,000 miles on the clock, original transmission, basically factory everything as far as drivetrain components (99% sure). My issue is that today my tach has started reporting lower than normal RPMs for various speeds as well as the shift points.

For example: normal behavior for driving 75MPH would be ~2250-2300 RPM, but now it's about 2050. Additionally, when accelerating at normal pace, gears would shift around ~2100-2300 RPM but now they're shifting at 1900. But the engine pitch sounds the same (at least to my ears and I generally pay pretty close attention to this since I love the sound after installing a cold-air intake 7 years ago) at all times, including the shift points.

This issue happened earlier this year however my battery was due for replacement and while I'm not 100% sure it went away before replacing it, I can confirm that until today it hasn't happened since.

Today it was fairly cold (17F when I drove into work) but my car is garaged and it's roughly 60F in there. Is it possible the cold temperature could have this much of an effect and that quickly? If not, am I looking at a transmission/torque converter issue? I'm all ears.

 

[keakar]

sounds more like a bad connector somewhere not making good contact so its reading funny, or the tach itself is bad.

for the most part a tach works or it doesnt so its very uncommon to just be "reading wrong" so thats super rare but not impossible.

try taking the gauge cluster out and disconnect and reconnect the plugs

if that doesnt do it then do the same for the rpm sending unit in tranny

and it never hurts to re-check the tranny fluid level even though i dont think that could be it

 

[watson6505]

I know this is an old thread but I think I am starting to see the same thing on my 2006 V6. That or I just never noticed how low the RPMs were on the truck. Can anyone that feels their v6 is reading normal please provide some benchmark data for shift points and general RPM readings?

RPM Reading:
Idle
Cruising at 30mph
Cruising at 40mph
Cruising at 50mph
Cruising at 60mph

Any other useful information would be helpful as well. If seems as if my truck always wants to shift to top gear at low speeds to drive the RPMs down to like 2500 or under...sometimes even under 2000

 

[Run4Evr]

to much or low on tranny oil? I ran into an issue where the mechanics over filled my tranny and the rpm was abnormal. after research they added the correct amount it was back to normal but worth a shot to look at.