hesitating motor

[90240ka]

I have a 90 240 coupe, and I have tried countless times to fix this problem.

Problem: When I start my car, my revs steadily drop from .837(normal idle) to .350 then jump back up to 1.40 and it does the same thing until the car has totally warmed up, then is stays in between 1.000 and .750

Solution: I have bought new fuel injectors, plugs & wires, Fuel Filter, I am tempted to buy a new fuel pump, but thought I would come here and get some suggestions, before I spend more money, and not getting the problem fixed.

I also have another problem, my heater vents are not working, my defrost works, that is my only form of heat right now, I dont know if this is mechanical or and electrical problem. if you guys could help me out it would be greatly appreciated.