I'm trying to figure out the curb idle for my 2.3 with 4 speed should be set at. I'm also wondering why my pinto would be popping through the exhaust when shifting and on deceleration.

My Clymer's manual says:


 "Curb Idle (solenoid - On) 1973-1974  See emission decal" Well, isn't that a great help. 


 " Idle Speed (solenoid Off) 2.3 (thru 1976) 550 RPM"


My Haynes manual...,though it states "thru 1974" does not even acknowledge that ford used a 2.3 in the Pinto in '74! 


My Pinto came with a 2.0 and a missing Decel valve. I then went immediately to a Turbo motor. So, while lacking that knowledge..., you might want to investigate the Decel valve as a cause because the problem seems to occur when you lift the throttle. It is during those high vacuum times that the valve is active. That said many people seem to remove them because they are a problem.

Just remember that a 100,000+ mile Pinto is not likely to idle at the same RPM as a new one. Play it by ear and you'll be ok. If the car will move fast from a dead stop without touching the gas pedal your idle is most likely too high.