Rev Limiter Problems!! Please Help!!!!!!

I Have A 94 Civic Coupe Ex (d16 Z6), And It Has Always Run Fine Till Now, The Rev Limiter Has Always Kiked In Past 7200 Like In 7500 Or So, And The Redline In The Rpm Gauge Is At 7200, But Now It Limits At 6000 Or Some Times 6500, I Havent Ake It To The Shop Im Months, Havent Mess With Anything Electrical, All I Did Was Change A Radiator Hose That Wasnt Even Broken, It Was Starting To Look Like A Ballon When It Warm Up, And Thats All Ive Done To It, I Know No One Beens Mesing Around With It, And Haven Race It In Months, I Do Have A 2001 Civic Oil Filter And I Notice Its A Little Thinner Than The Original One, Its Still Original From Honda And The Guys At Tune Shop Said It Would Work Fine, Ive Never Heard Of Nothing Like Tis Before And Ive Been Around Hondas For Quite A While, At First I Thoug It Was Due To A Cold Engine But It Does It At Normal Operating Temp.

Any Help Would Be Apreciated Thanx!

sounds like timing or distributor problems. You havent messed with the timing on the distributor have you? All those other things you mentioned are pretty much unrelated.
Also, do you really think you have a B16z6 under the hood? lol

lol notice the edit....

i havent mess with anithing like that, i do have a small leak of oil coming from the ignition, but it been there for months, jejeje D16Z6 nick was already taken!
thanx for he info, guess il have to take it to the shop.

ok guys problem solved! it turns out to be the tach was bad, it has a small knob inside that neded tuning.