Ford Repair: Check Valve?, valve lifter, ford guy

Question
I have just bought a 1985 Ford Ranger (2.8 carb.6 cyl)and the seller said something to the effect of a cracked or broken check valve?  I'm not a Ford guy and cant find anyone around to fully answer my question.  Yes or No.  Is there a "check valve" and where might I find it? I experience a hard time starting (cold morning?)and maintaining highway speeds.  I've replaced spark plugs, wires, air filter, pcv valve, fuel filter. Help please, Thank-You in advance.
Kevin

Haynes and Chilton have no real topics on this subject.

Answer
KEVIN

a check valve is a ball that operates a seat located on the valve body.the check ball operates by having a fluid pressure operated linkage force it againest the ball seat to stop flow. having said that there are many places you can have a check valve. by your problems you have i would say its your hydraulic valve lifter.hope this helps.

ken