bobs88 Greetings...new member here. I am original owner of an 88 GTS 4AGE 5 speed, fresh rebuild (but this problem was happening before the rebuild). It stalls (or at least the idle drops so low it wants to stall) after slowing down...usually after warmed up and driving on the freeway. After reading up, I feel it's the EGR or the IAC (both original) though please educate me as there are also the VSV and MAP sensor that could be problems too.Fix #1: I checked and adjusted TPS...no change. Also, fuel injectors and fuel filter are good.Fix #2: I removed the throttle body to clean the IAC but the 4 screws holding it on are frozen and I cannot remove it so I just sprayed it as best I could. No change.Fix #3: I used a vacuum pump on the EGR, and the diaphragm slowly loses half its vacuum over about a minute...does this mean it's bad?. My manual states that the vacuum should be low at 3500 rpm and zero at 5000 rpm and it isn't...it has some vacuum at 3500 but does not change to 0 at 5000 rpm. As an experiment I temporarily disconnected the EGR (plugged the vacuum line going to it) and did some freeway driving to see if the problem would stop, but it hasn't. Does this "check" eliminate the EGR as being the culprit?Thanks in advance for a long question.