Misfire and oil on my 300zx

[echonightsi]

So I am pretty sure I have a misfire in my nissan 300zx 1993. It has low low low torque, it sounds very rough and what I think is a skip at low rpms, and lastly after replacing all the spark plugs with the colder plugs, one of the plugs, number 6, was badly covered in oil. With the new plugs it still skips. Any idea/experience whats going on before I sell my left nut to a mechanic to find out whats going on?

[NolimitZ32]

If the plug is covered in oil you either have bad rings or bad valve stem seal. This would also cause the plug to not produce a spark causing you to run on 5 cylinders, causing a miss, loss of power, etc.

[echonightsi]

If the plug is covered in oil you either have bad rings or bad valve stem seal. This would also cause the plug to not produce a spark causing you to run on 5 cylinders, causing a miss, loss of power, etc.

Would this cause the rising loss of power from lower rpms to now higher rpms, because when I first got it everything to 3k rpms was like driving a civic, and then 4k on it was like a turbo kicked in, but recently the loss in power is rising to 4-5k rpms.

[NolimitZ32]

There are too many variables to pin point it past this without doing further testing and troubleshooting, in short yes this could be tied to a "rising" loss of power. Generally at higher RPM its easier for the engine to spin so it may feel like you are getting more power or it may have something to do with the variable valve timing. Like I said too many variables.

[echonightsi]

I understand the variables, I know the random smell that is coming from it when the lower power is at its finest has something to do with it. Problem is that it doesnt smell like rubber, gas, or oil, sooooooo Im getting angry at it

[NolimitZ32]

Does it smell like sulfur? Rotten Egg? If so you likely have a clogged cat.

[echonightsi]

It might, it doesnt smell fantastic thats for sure. Ill ride around in just a sec and check, although I was gunna replace the cats with glass packs (not in the same place).

[NolimitZ32]

Just get test pipes in lieu of cats and a decent catback.

[echonightsi]

well unfortunately I just put a little money into just getting some mufflers welded on to keep my happy until my TT swap. It would be a shame to replace that just to replace it again down the road.

[NolimitZ32]

If money is any issue just pull your Cat section off and hollow them out. This will by all legal definitions make your car illegal for road from the EPA's standpoint but so will replacing the cats with anything but other compatible cats.

[echonightsi]

EPA who now? Environmental Poser Agency? I already have cute baby rabbit skin seat covers so they can suck it. (I do not)

[echonightsi]

Ok quick question, I pulled the coil on the 6th cyl just to do a cheap quick test as to why it has fuel and or oil on it and the new/used coil pack I got looked different when it came to the spring. Why is this, it came off a 92 nissan 300zx so why would it be different? Seems to be working fine/the same . // ///// / / / / / / /

[echonightsi]

This is dead but just for anyone who has this exact problem and stumbles upon this. Injectors, replace all the injectors. One was leaking hard and spraying to much fuel.

[Ace2cool]

Thanks for updating with the solution. Sorry no one got around to it. Yes, the excess fuel by a stuck injector can dilute the oil on the cylinder wall and cause it to build up on the plug or sometimes even show through the exhaust. Can look like failed piston rings, and can eventually CAUSE failed piston rings due to lack of lubrication.

As to the other coil pack, the cap that goes on the tip of the plug is broken off. If it's working properly, it's probably because the spring is still completing the circuit.