93 4x4 not shifting at med. speeds 3rd 4th gear

My high mileage 93 pickup 3.0 v6 (auto) is not shifting correctly. It seems to shift through 2nd flawlessly but when trying to get up to freeway speeds it seems to not be hitting shift points for 3rd and when it does rarely get into 3rd it won't go into 4th. Consistently runs at 4500 toms at 50-60 mph and letting off the gas does not downshift. I have read a lot pointing to everything from solenoids to throttle sensor. Anyone have any advice for where to start? Thanks!

 

You have an early computer controlled transmission . Check the fluid , then scan for codes .
Can you identify the vin code . trying to figure out which trans you have
Got some info here that may help
http://www.tacomaworld.com/forum/te...warner-340-series-transmissions-write-up.html

You should have a cable running down to the transmission that tells the transmission where your foot is on the gas pedal known as the throttle valve cable . Your going to have to make good and sure its adjusted correctly as one of the next tests

 

So you recommend changing fluid and adjusting cable as first test? I have read some things about that cable rusting and needing to be lubed. It seems like it must be some kind of communication problem when it does shift it shifts smoothly no knocking grinding or jolting just not too sure how to go about pin pointing it. Thanks!

 

Not changing the fluid yet, but making sure its full of fluid when the engine is running in park .
Still having a rough time identifying your transmission . Its either a 340 or a 340e . Your truck was one of those inbetween years where Toyota started going fully computerized

 

I will check first thing thanks again

 

checked the fluid looks good, found that with that chart you sent the link for this is what I am running...

*A340H are found in 4wd 4runners and trucks that have the 3.0L 3VZ-E< V6 motors.

 

Yes ,you are correct . If the fluid is good , scan for codes is next .
Autozone scans for free if you dont have a scanner
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tested using the paperclip method and the check engine light blinks continually telling me that there are no codes being thrown. lost as to what to do here

 

Testing for codes with a paper clip is a pain but it works .
With no codes present that pretty much takes care of anything computer controlled such as solenoids and the various sensors including throttle position .
My next step would be removing the transmission pan and inspecting the bottom of the transmission for debris .I hate to say it but things dont sound good . Possibly a stuck hydraulic spool valve in your valve body .