A guy was moving and gave me his Maxima.. I had been without wheels for several months, so this was a godsend...
He said it had a broken motor mount. I said thats not a big deal I can fix that no problem.
Well, when I put a battery in it and started it up, it was clearly a miss and I didnt think it was the motor mount at all.
The next morning I pulled the 1st plug wire and there was no difference in the way it ran so I actually found the bad one on the 1st try.
I left it out and cranked it and got about a 3 inch spark so thats not it.
I stopped by my uber mechanic friend who did a few shadetree tests and said it was a bad valve and not the intake..
I did a compression test and it only has 30 lbs of pressure.. Bingo, right? But what now? I did a head job on an '80's 4 cylinder Nissan back in the day.
And Im an ok mechanic but not much experience with nissans. I'm a poor person and need to do everything I can by myself.

 

Check your coolant for bubbles, check you oil for water. Perform a leakdown test and determine where the compression leak is:
1. Intake (air hissing on intake side will be heard.
2. Exhaust (Air hissing in exhaust manifold/exhaust system.
3. Rings broken or stuck (oil hissing in crankcase (oil filler/ oil dipstick tube).