well i got a problem witch i cant find so far. wen i bought my 2002 vitara with the 2.0L it was smoking black a bit wen reving it up and had power lost, i got new set of spark plugs in and now the smoke stopped and the power stayed the same, it runs smooth and no miss. i have make sure everything on the brake system is free (dosent stick on) and the wheel bearings are fine. wen i say power lost i mean its bad, i can barly reach 100km/h and takes forever. i do have bigger tires 225/75/16 but it so bad that i know that is not the big issue, it is also so good on gas so it cant be sumthing to bad to fix. so far im thinking maybe the gas filter??

Gas filter may be good to replace if your truck has over 150K on it and the filter was never changed.  Even with larger tires.... you have lost some of the stock gearing mechanical advantage... but it should still accelerate up to 80-90MPH.  It would just take slightly longer to do it.

Is it a 5-speed or an automatic?  If it's an automatic, I'd look at the transmission.  Is it slipping?  Is it upshifting too soon (keeping the RPMs down too low for the powerband)?

Also, you say it's good on gas - does it have the check engine light on?  If so, have the codes scanned at a parts store and see what it says is bad.  If not, I'd still look at the O2 sensor, MAF sensor, and Manifold pressure sensor.  Those could all make it run lean, which would kill power (and make it run hot).

Hope that's helpful . . .

Clogged cat?

rear cat was removed a few month ago as it was clogged, yes the engine light is on, it says evaporation leak, its a 5 speed tranny, i am hearing a noise wile driving, i thought it was the clutch release bearing but i think it might be my tranny or t-case, so i think this may be my issue.

if your rear cat was clogged a few months ago and it was still throwing fuel down the exhaust because of a the bad plugs. it could be the front cat that attaches to the manifold. if it is clogged alittle you can get some hissing noises as the press through the clogged cat. i was getting some weird sound out of a old swift i had once, sometimes when i would turn it off it would sound like a tight fart LOL. once i took the cat off worked fine.

that cat is fine, we took it off to check it.

had nothing to do this rainny day here in new-brunswick canada, so i play around switching parts, and tried the gaas filter first and that made quite a difference, and that was switching with an old one too. so im buying a new one for it for sure as i know that might be my whole issues, and my tranny noise is getting worst, i know the clutch release bearing is bad but the tranny might be bad as well as in 4th and 5th gear the noise is not noticeable, might be the humming tires that hides the noise,but since i got a junked vitara with a good tranny and newly rebuild t-case im gona make the swap soon.