Problems for future reference. I had a bad modulator valve. It would cause the 302 to run rough and die going down the road at 70 MPH. This took a week and changing out most if the ignition system. Thought this might help someone in the future.

 

Yep. Ford modulators fail and leak vacuum, which is nicer than Chevy failures which suck tranny fluid into the engine.

 

Can a Ford Modulator suck tranny fluid into the carb if the level is too full and the modulator opens?? Im just trying to figure this out...Under part throttle...bringing the rpms up in my truck at a dead stop on the breaks the engine wants to die out all of a sudden between 1000 and 1200 which is my launch point...and all i did was change the filter and fluid in the tranny...thinking i put too much fluid in, and its being drawn back up....in 1.5 hours im gonna check the level again, and drain some out if the level is above the modulator...

--John