parts changing is not trouble shooting
 

Always treat a problem like a homicide crime scene, look for clues, dismiss those that aren't related (test to verify) ask yourself why wouldn't it be the part you selected, but the communication or mechanics, if you are unfamiliar with them, you're probably off track. use logic/common sense, exercise process of elimination (algebra), Simplify & Reduce test hypothesis, verify parameters, now you'll be on the right lead! HEYYY!! YOU THERE!!! Don't swap n hope, "Swapper No Swappin!!!" WELL... You stand a chance of creating another code or obstructing the right one, masking a condition before pinpointing it.
Breathe, relax, research, and for sanity's sake, do not guess!! That's hopw footballs are nearly intercoursed by monkeys!!
--Ready!? (no) --Fire! (bang!)---NOW I meant AIM DAMMIT! AIMMM!!! Heyyy, I get it!!!
Know your gear, learn the processes, functions, concepts, the factors, non factors, the weak links, and finally flush out the common denominator. This is the correct product of, and the reason why methods of troubleshooting shouldn't be deviated, or cost anything (very little) to determine! Be sure to keep a log, simple and directly to the point, don't forget to note date, mileage, and all contributing conditions upon onset of a problem.