Hello I am new to the forum and I am hoping to meet people who can teach more about the 4th generation Maximas/ I30's ... the good and the bad.
I am interested in purchasing a used 4th gen Maxima or i30. Hopefully a 1999.
Any thing I should be looking for when looking at the cars? Common problems?
A friend said he heard that "they have the tendency to overheat the engines, and in turn burn out the spark plug connectors that are a bit expensive to replace.", but im guessing that only applied to certain years.
Just not sure to which years it would apply.

The are great cars and the motors last a long time as long as they have been properly maintained (Ward's best engine list for appx 14+ straight years). What your friend heard is a bunch of bull. Most problems seem to be MAF or sensor related with some injector replacements needed as mileage increases. Nothing I don't see with other vehicles of that era.

Make sure the one you are looking at has proper records with it.