Rej Chartrand

Hello. I'm new here. I've owned my 300zx for about 6 years now. It has always ran well up until last fall when it was having hard starts. Hot and cold. And eventually began stalling. It has become increasingly harder to start. When I turn the key I hear the pump prime. The engine turns over but rarely starts. When it does it will run for about 1 - 10 mins before stalling. It stutters a bit before stalling. If I keep the throttle open it stays running, but sometimes that doesn't help. I've checked the vacuum lines and everything seems fine. When the engine is running it runs smooth with no hissing sounds (vacuum leaks) until it eventually dies.*
I replaced:
Fuel Filter
PCV valve
Plugs
Distributor cap
Distributor rotor
Ignition coil*

The reason I changed the coil was that there was no spark coming from the coil. Which leads me to believe this might be an electrical /ignition issue. Could this be the cause of a faulty ecu or ignitor?*
I hope that someone here may have some insight.

rogerz

you don't give a lot of information on what you have checked other than throwing random parts at it. here is a few guesses.

Get your battery load tested. Be sure you have clean, tight corrosion free terminals on both ends of your battery cables. Be sure the ground (negative) cable goes to a bolt into the frame before going to the starter. grounding through the starter is not a reliable connection. Z's don't like low voltage. causes the electronics to act funny. it is possible to have enough amps to crank but not enough voltage to run the electronics. If you have one size fit all cheapo clamp on terminals they are a problem waiting to happen. Usually on a rainy night around Oh Dark Thirty.

Clean the connectors for the maf or afm, ecu and tps. Deoxit by CAIG is probably the best connector cleaner on the market. spray with CorrosionX after cleaning and before putting together this will help prevent any further corrosion. DON'T USE DIELECTRIC GREASE.

check fuel pressure at the fuel ring. check vacuum with a gage (they are cheap).
new set of plug wires never makes things worse.

CHTS is always a good candidate for the type problems you describe