!!!-Need Help/Advice-!!!

Ive been working out seriously for about 4 years now and i started out getting bigger and stronger and then it just all stopped. For the past 2 years i havent had any real improvements in size and strength and i want to know why!? I'm currently 20 yrs. old 6''1' and 215 pounds. ive been this size for the last 2 years. I eat around 3000 calories per day and even have raised it before but started putting on alot of fat. I take cytogainer and im taking n.o. explode, ive also tampered with some prohormones here and there but never found results. I train around 4 days per week and this has been my routine.
(note i switch some workouts with thers from time to time for change)

MON-(Chest)

flat press 4/failure
incline press 4/failure
cable crossover 4/failure
pushups 2/failure
Ab-circuit-15 min.

TUE-(Back)(bis)

Pullups 2/warmup
lat pulldowns 4/failure
cable rows 4/failure
barbell rows 4/failure
reverse grip pulldowns 4/failure
deadlifts 4/failure
preacher curls 4/failure
hammer curls 4/failure

WED-OFF

Thur-(shoulders)

barbell press 4/failure
lateral raises 4/failure
barbell shrugs 4/failure
rear lateral raises 4/failure
dumbell press 4/failure
AB-circuit 15 min.

Fri-(Legs)(triceps)

squats 4/failure
leg ext. 4/fail
leg curl 4/fail
lunges 4/fail
calf raises 4/fail
push-ups 4/failure
cable pulldown 4/failure
close grip 4/failure

Any advice would be great thanks!!!!

Why in the world would you train triceps with legs?...why not train them with chest??

As far as not seeing results, you can only get so big and then you stop. At this point, you would have to bust your ass just to gain a pound or two of muscle. That is just they way it is. I assume you have never juiced?