Hey guys so I'm new to the forum I bought a 03 g35 sedan about 2 months back now it's belching smoke out the exhaust and the engine isn't running smoothly what could it be?

 

Typically that means your piston rings are fried, sometimes it's a sucked valve or other various mechanical failures.

Do a compression check, that will tell you a lot.

Best case scenario it's not actually smoke but there's a high likelihood the motor is shot.

 

So I would most likely need a new engine? Or can this be fixed?

 

You need to troubleshoot the problem, first step is the compression check.

 

Also, anything aside from a cracked block can be fixed. The two limiting variables for most folks are TIME and MONEY.

Rebuilding the motor if necessary is cheaper than buying a pre-assembled long block if you're doing the work yourself. If you are paying a shop to do the work then you compare the cost of a long block vs. the cost of a used engine and decide if it's worth it to YOU to put another motor into the chassis (full rebuilds of the existing engine are usually more expensive due to labor hours spent and thus most folks don't have it done like that). If the mileage is high enough then another option is to just part out the vehicle and buy another one.

Decisions, decisions. Step one is to troubleshoot the problem.

 

Thank you it was helpful I'll see if I can make the best of a bad situation and do a engine swap