1997 Stagea S2 Misfire

[CanadianStagea]

I live in Canada, have a 1997 Nissan Stagea Rs4 with a s2 Rb25det in it that was imported from Japan couple years ago. I've recently had a major misfire problem that I am lost as to what is causing it. It is very random, comes and goes as it wants it seems, have recently changed coilpacks, spark plugs, coil pack harness. Also has new 02 sensor, fuel filter, air filter, etc. I had the car in at a local shop that deals with import vehicles. They looked it over and came to the conclusion it was the plug on the coilpack harness for cylinder 4 that was not making contact as they could wiggle the plug while it was misfiring and it would smooth out.

They told me 100% that it was the harness. So i bought an oem full harness. Installed it and the car ran fine for about 20 minutes. Then it started happening again. They also smoke tested it and it came out fine, no leaks. At this point im leaning towards injectors, but im looking for any other tips or if anyone else has had a similar problem, as I dont want to have to buy injectors if I dont have to.

[FireFox-89]

I've read that the RB25 engines are prone for the coilpacks not working correctly. Have you tried moving coil packs around onto different plugs to determin which pack it is?

Edited April 18, 2015 by FireFox-89

[CanadianStagea]

I have tried moving the coil packs around. Moved number 4 to number 1 and the problem seemed to continue on number 4.

[FireFox-89]

I have tried moving the coil packs around. Moved number 4 to number 1 and the problem seemed to continue on number 4.

Could be a spark plug issue. I would probably take it to a garage before replacing any parts

[KiwiRS4T]

You could get your injectors cleaned and tested.

You haven't mentioned the afm. You could try cleaning it and also checking the plug.

[Dan_J]

I have tried moving the coil packs around. Moved number 4 to number 1 and the problem seemed to continue on number 4.

weighing up the costs you could just up grade the system to ls2 truck chevy coil pack seeing as you are in that neck of the woods.

i guess the cheapest way to confirm this is to chop the suspect plug off (with some wire still left on the plug so you can solder it back on if its not the issue) then re-pin those wires on the loom with individual speaker wire crimps ( or what ever size suits), sleeve the crimps in heat shrink from tip till exposed wire and use a pair of pliers to crush the crimps down a tiny bit so it holds tight on the coil pack

unless the signal wire for no. 4 is damaged in the main engine loom

Edited April 19, 2015 by Dan_J