Ok, I have just read through 17 pages and have not seen anything describing my cars problem---My 91 Maxima has a mind of its own--Half the time it will start up fine, but on colder damp days or even days where there is just a drizzle of rain ,my car cranks and cranks but will not start--I can try this for 15 minutes of constantly trying to start it and it wont even act like it wants to start, but i can go out several hours later and it might do the same thing or it might take right off like nothing was ever wrong. Also I notice when I do have it running and I have the heater on with defrost that the air will all of a sudden keep getting cold then warm, cold then warm and this is even after I have had it running for over half an hour. Any suggestions will be greatly appreciated.

 

get a new distributer cap. This is a common problem and I have had it happen 3 times on my VGs. Replaced the cap and it fixed the problem.

Go ahead and replace the rotor as well while you are at it.

The cap gets cracks in it and condensation gets in there and prevents it from cranking.

Try to get an OEM one if you can. I had an aftermarket one fail (why its happened to me 3 times and I only had 2 VGs) within a year.

 

If the car history has coolant spill (as u air bubble problem suggests), then u ign & other wires have remnants of glycol. These tiny particles act as sponges: on wet weather they suck water from humid air, on dry day release.

This water conducts electricity, and not surely to spark plugs...

Clean all, buy new soothoses from NGK or make real conductors,
read this and more: http://www.cardomain.com/memberpage/748507/12

 

I own a 91 maxima SE and my heater was doing the same exact thing (cold to hot and hot to cold, no matter how long the engine was running for).
I just got a tune-up done about 2 months ago...and figured since winter was rolling in that I'd also flush the radiator as well.
Ever since they flushed the coolant, my heat has been working GREAT (like it did before). I would suggest getting a complete tune-up on your car. (Since others have suggested replacing the distributor cap and rotor for your starting problem).

Just get a complete tune-up and flush the radiator. It will probably solve your problems, but even if it doesn't, getting a tune-up definitely could not hurt.

 

thanks for all the help--i will do these things and hope they work--i think they will take care of my problems, once again thanks.