i just bought my jeep and when i test drove it about a month ago it ran great. now when you drive it it wont up shift until about 4500 rpm. when you can get it to shift to third you must stay in the gas or it will down shift. it has 4 liter and aw4 and np231. i am an auto tech so i am good with technical stuff just no idea where to start.
it has some vacuum leaks and whoever had the car before thought they knew how to work on cars and have really done some crap.
any body have a good vacuum diagram with connections and all?

 

what year is it if its the aw4 its not vacuum controlled
it has a control module under the dash

 

if the vac to the map sensor is bad it could cause a shift problem
do to the pcm not getting the right info

 

i just redid the vac line to the map. it is a 91. i have already duplicated ground to the control computer as per the tsb. i have also checked the ground on the tps but have not yet had a chance to check the output of it.

 

you need to check the connections on the TCU its under the lower dash panel middle driver side

 

un plug the TCU and try to power the solenoids manually

to test if they are working properly

 

whoa! could i use those wires to make a manually shifted auto? anybody tried it?

my tps only reads .8 at all throttle positions... bad?

 

yes you can and yes you can find lots of wright ups and some kits

 

http://radesignsproducts.com/default.aspx

 

hear is a diagram it shows were to put the diodes to stop feedback