When i am coasting, only coasting, the engine will want to die but if your are sitting still it idles fine and you can rev it all day and still be fine. My friend did say that this was caused by the EGR valve and the engine is timed, i just checked that. A few winters ago i did do a rebuild on the engine a 3.1L and even then this didn't start right away, this started this year.
Update: I have replaced the gaskets on the EGR valve but nothing changed and then i took the EGR off and put a block off plate in it's place but still the same results for the stalling while coasting

 

Is it carbed or injected?

 

Its multiport injected and I forgot to mention that it's also a manual.

 

UPDATE:So i just tried to take a leaf blower to the motor and the sensors to see if maybe the wind from driving was causing the engine to stall but no go. the engine didn't change RPM's at all.

 

By coasting you mean you have the clutch pedal down so that the engine can idle?

 

i had the same issue with my 305 tpi. it was auto, and when i would let off going onto off ramps, it would stall out. i never did find the issue, but i believe it was the iac. it would idle fine all day, but it would stall out on off ramps

 

UPDATE:I just got done checking the air duct and it looked fine but i'm about to tape off one end and fill it full of water to check for smaller cracks. and i also checked the vacuum lines, there was on that needed to be replaced which i did but that didn't change anything. what i'm also about to do is get the rear end off the ground and let the tires spin and see if the engine dies and do it again without the VSS connected.

I'll let you guys know what happens after i get this done.

 

UPDATE:the problem is fixed. it was the VSS (vehicle speed sensor). i got the rear end up in the air and let the tires spin with the VSS connected, which the problem occurred, and then i did it again without the sensor connected. i took it around the block and no instance of the problem!

 

odd. but now your speedo wont work

 

Yea for now but I just have to change out the sensor then the speedo works.