is there a code to instantly complete a mission? im stuck on 1 mission and i cant beat it..

hmmm I don't think I've heard of such a thing.

However there are a variety of people here who have finished
the game more than once and could give suggestons on any mission in the game.

And there may be something in the FAQ section that could help you. Glenster's FAQ is a great read with a TON of information but it might not have specific hints. Other FAQs do give specific hints.

What mission are you stuck on? Maybe someone here has a tip to help you with it. If you get really stuck someone may be willing to do it for you. Help us to help you

right, specify the mission and what to do in it.

im stuck on ug loc and driveby

There are plenty of sites that let you download savegames (for PC) with missions completed. I hated many of the missions in this game they frustrated the hell out of me!

Og Loc, don't bother shooting, just stick with him. And try not to crash the bike too much. Driveby, if that's the one where you have to waste groups of Balas, Do some shooting yourself. You can also get out of the car and pick some of them off from a distance if you've got the right weapons.

no theres no cheat for completeing a mission but og loc mission just drive carefuly cuz the guy ur chasing will wait for u and u will end up to a basket ball court then start shooting