ok... '93 gmc jimmy tahoe xl blazer, in park starts, revs just

[zen_ewok]

fine,(auto tranny)put in gear2go and dies,help! fuel filter not plugged, tranny somewhat new, fuses good ,yada yada, im really confused trying to help a friend.
you can put it into gear and hold it there with the break on, but as soon as you let off the breaks it just dies, the tranny was professionally installed and worked great up till this. yes there is plenty of trany fluid in the transmission.and overall the vacume system appears visually intact. any ideas? i sourced through a chiltons but found it to be of little or no help(plus i am half an idiot sometimes)so there it is , hopefully someone out there in the matrix can shed some light on this grey area for me. thanks, zen.

 

[robertb0320]

The first thing i would try is to see if it starts in Neutral.. but it sounds like you have some sort of vacume problem and when you are putting a load on the engine it just quits. check also the pcv valve (positive crancase ventilation..it plugs into the top of the valve cover..just pull it out and shake it making sure you here it rattle. then check all the vacume lines as its a 93 and they are probably in need of replacement....If that doesn't work...trade it in on a FORD