Fuel Injector replacement cost on 2001 Ford Ranger

Check Engine light comes on, goes off. Ford mechanic says fuel injector need replacing. Also, Check Gage light stays on, (Oil pressure sensor replaced, now off) Ford computer evaluation & codes showed all cylinder's firing after replacing all 8 spark plugs, however, truck dies at slow idle.
Q: Will Fuel Injector repair problems?
Best guess for estimated cost to repair & replace as described above?

Asked by for the 2001 Ford Ranger
If you can post what code is being set now, that would help. And as I understand it, the problem now is that the engine is idling low and stalls?
The first thing to do for a low idle speed is check the idle valve, they get dirty and cause a low idle speed, and will cause the engine to stall. Sound familiar?
Let me know what you find out, based on your information, I don't think you have a bad injector.