I changed my oil and under the oil filler cap there was yellow gunk. There was a trai of yellow fluid trailing dorn from the filler cap into the engine. There was a small deposit of yellow gunk up in the top/inside of the filler cap. What is this stuff?
I've been using synthetic 5w20 for the past few oil changes after buying my 06 trd used. previous owner used conventional.
I changed my spark plugs approximately 1500 miles back. Other than that I don't know what else to add.
I'm concerned that when changing my spark plugs (for the first time) that I frigged something up because my fuel economy has been crap lately too. (might just be because I'm running 265/75/16 studded mudders)