on the top of the transmission
check the vacume line to the trans if that is good change the vacume valve that the line goes to.
find the vacume line and check for a leak in the system
On my 1994 achieva its vacume controlled i had to replace the line going to the controller. It was broken. It runs frin the top of your intake throttle body its a small line maybe 1/8 inch down to a vacume tank in lower front drivers side, from there it runs up the drivers side fender accrossed the firewall towards the top and into the passanger side through the firewall. It comes though behind the glove box and over to a vacume spliter behind the vent selecter. mine broke right at the vacume spliter. Word of advise use heavy stiff plastic vacume line to replace it anything less will colapse when vacume is applied. this solved my problem. the line is very easy to replace.
you may have a vacume problem.Most likely the vacume line thar goes from engine,through the firewall.This hose is made of a hard plastic.Over time,it will get brittle and break.That is where I would start.Look on the pass side of the firewall where the wiring harness goes through.That is where the vacume line goes through.
get yourself a HAYNES shop manual haynes does not have vacume diagrams have the book for a 1993 and no vacume diagrams need 1 myself
sounds like a vacume leak! check your vacume lines and block off the brake booster line. may be a defective booster.
i just need the vacume line routing schematic for a 91 gmc sonoma with a 4 banger
Poor seal or it may be a breather if has a vacume line.
looking forward on the right side of manafold..follow vacume line from throttle body
check for a loose or broken vacume line on the engine probably on the intake
check thermostat to be sure enging is getting hot. Heater control on dash opens doors to direct air flow. check that cables are working behind the dash control. you should hear the doors open and close. Also there are vacume operated doors. Srart with replace vacuve lines on engine. At the front of vans, as you open the hood there is a round plastic vacume chamber. It is easy for the vacume line the come off there. There are "vacume engines" that make use of the vacume to open the doors. These can wear out. Mine has always been vacume lines either broken or disconnected.
it is at the receiving end of the fuel rail that feeds the injectors.It has a fuel line attached to it and a vacume line....seen one you seen em all.......