I recently got a 2004 g35 coupe with 130k miles. I noticed when I turned the car on a small amount of smoke would come out of the exhaust pipes, and when I rev it a large amount of smoke comes out. The smoke is a blueish color. I heard it may be some kind of oil leak, I checked the oil cap and I saw a small amount of smoke coming from there also. Today the car began to shake/vibrate at idle. I got the car about a month and a half ago. The check engine light turned on about 3 weeks ago. It turned off on its own for some reason at the beginning of the week, but it turned back on today.

Does anybody know what might be wrong with the car and what it would take to fix it, or has anybody experienced anything similar?

 

Use an OBD2 scanner to see what the code was, post the P#### code or look it up on the internet.

Smoke from the tailpipe on INITIAL START is typically worn valve guides. Smoke from the tailpipe on HIGH REVS is typically worn piston rings. It sounds like you have both.

I would perform a compression check of the motor, google how to do it properly or take it to a mechanic. Your compression results for a good motor will be roughly 180 per cylinder with no more than 10% variance between the highest and lowest cylinder (ideally no variance or only 1-2 psi).

It's possible your are mistaking the color of the smoke and the problem lies elsewhere but I suspect your motor is fried, this happens at about that mileage if the engine hasn't had it's oil changed at the proper interval, ignoring the oil and letting it go for 10k miles causes INCREDIBLE wear to the motor even if it's not driven hard. If the motor regularly sees high rpms the damage is even more catastrophic. Another major culprit is letting the engine run LOW on oil, if your oil level ever dips below the LOW mark on the dipstick (only check oil on a cold motor before it's been started for the day) you need to immediately change your oil because the amount of extra breakdown is substantial.

A well maintained motor that's driven moderately hard on a regular basis (think 5-6 high rpm freeway onramps per day under WOT) can be expected to survive until 200k. A well maintained motor that's driven LIGHTLY can be expected to see 300k.

A POORLY maintained motor might fail as early as 60k (or immediately if it's allowed to run out of oil) but is usually smoked before 150k. Moving parts wear at a predictable rate depending on the level of contamination in the oil, and the viscocity breakdown of the oil is directly related to the heat levels it is subjected to over a given timeframe.

 

If it's diagnosed with anything that is $1000, you can source a motor with less than 20k miles and be done with that issue: car-part.com