Hey everyone, I'm back after a nearly 5 year hiaitus. I sold my 95.5 many years ago, and just purchased a '01 Tacoma 4x4 w/ the 3rz engine. I'm really familiar with these trucks, and I'm going through this one finding all the issues, and there's a LOT of maintenance that was neglected. It's got 241k miles, but sounds as good as my 95 was.

When I bought it, the owner (who bought it new in 2001) provided me with a set of 4 new coils, and said the rubber on one of them was deteriorating and causing a misfire, which was absolutely true. He said he wrapped it with electrical tape, which was weird that he'd have the coils but not have replaced them. But, since everyone has their reason for selling, I was sort of like whatever. Yesterday I changed oil, swapped plugs, and coils also. When I pulled out #2 and #2 plugs, the OUTSIDE of them, especially #3, was covered in a fair amount of oil, however the spark-end itself was spic and span on all 4. I looked down while the plugs were out and certainly there's some oil, but nothing ridiculous. I assume the coil boot deteriorated a little because of the oil in there, creating a wet situation and causing the misfire.This is where my knowledge of the 3rz engine is lacking. I've never had to get inside one before, so I'm not sure what would allow oil to seep in. I mean, the spark plugs are above the head gasket, and I've not seen any sign of any oil in cylinders, water, or any actual sign of leakage. Once the new plugs and coils were in, it made a HUGE difference in power.

Any idea where oil would be seeping into that area from?

 

The spark plugs on the 3RZ have a tube that goes through the valve cover (if I remember correctly).

You probably have a few spark plug tube seals allowing oil leaking into the tube.

 

Hopefully it's just oil from an old valve cover gasket that WAS leaking and P.O. did not clean if after leak was fixed. Speaking of leaking valve cover gasket, I need to fix mine, too.

 

Thanks guys! After a talk with a neighbor of mine yesterday, he confirmed what you guys are saying. There's o-ring gaskets around the spark plugs that are probably leaking after 241k miles. I'm going to order a new valve cover gasket set and replace them all.