Hi my name is Gene and while i don't own a car i do have a 2002 A15. the engine has the equivalent of 300,000 miles. I have checked your site for years when i need info for my engine . I hope y'all don't mind. It is the powerhouse for a carpet cleaning machine. its been having a strange problem lately that i have not been able to diagnose. it will go from 2500 rpms down to around 500-600 rpms and sound like its under water. it will run for 6-10 hrs a day just fine and somewhere during this time it will have this problem for maybe 5 minutes and then it goes away. i popped off the distributor cap and noticed the center contact for the rotor was completely gone. not sure how it would run at all but it does. i replaced it thinking that was the problem but it wasn't. i have the ignitor module but im not sure how to get it out. Do i push out that small pin to remove that gear ? i appreciate the help as it will probably be one way. Any ideas what would cause the strange problem. IT has the Mitsubishi distributor.
http://s230.photobucket.com/user/Gene ... 0049_zps97810332.jpg.html

so i figured it out. so here is how i did it. remove the screw in the middle. lift and turn the shaft so it stays up. use a small punch and out it comes. i placed 2 earth magnets along side so catch it. it's very small and it can end up inside of the engine if your not careful. the gear comes off and you can easily replace the ignitor . then reverse.

any ideas why the engine would suddenly sound like its underwater and go from 2500 to below idle ? i hope replacing the ignitor solves it.

Hows the PCV system on it?
I once blocked off the port in the rocker cover, and when the pcv valve sucked the hose flat, it stumbled right down to bugger all revs.

I suspect the carburetor.

The distributor is the stock 1990-up Japan unit.

It is fuel injected so I know it's not the carburetor however I never thought of the pvc valve . If I shake it should it rattle. It's been so long I can remember. The ignitor did help now it doesn't sound like its underwater any more or at least it hasn't repeated itself. Now it seems to want to die and then it's just fine again. The engine typically runs for 2-5 hrs at 2500 rpms under a heavy load . Then on to the next job and repeat. It's a ghost problem I can't make it happen and now it last for less then 1 minute and solves itself. I did go ahead and replace the spark plugs with NGK gr4 gapped at 44. It still has the original coil and wires but they seems fine. It has been the best engine I ever owned . Does it use a standard 12 volt coil. No harm in replacing it.

Gene

It does not use a standard coil, but uses a Nissan high-energy coil. From the symptoms you describe, I am certain it is not caused by the coil or the spark plug wires.

.044 is quite a large gap. The -11 plugs are gapped .039-.043.

I can re-gap at .039 although It runs smooth as silk except the little hick-up. I do think its well over do for a new coil and spark plug wires. Which coil should I get

Gene

Nissan coil part number 22433-11M00.

Did that underwater thing again. Next time I will try to record it I will check the PVC valve

Gene

So this engine does not have a pcv valve. it has a vent that goes straight into the fuel injection.
here is a video of it doing its under water thing. it was at 1900 rpms when this started under load. to fix it i set the engine to 900 rpms and turned off the pump which removes about 5hp. it then self corrects. it is not the computer because i have 2 and it happens exactly with both. i reprogramed one just to be sure and it doesnt help.

http://youtu.be/8wVImu2wQKc