crazy_horse3030

I posted in a previous thread I am trying to replace my pcv valve.

But the point of this thread is to question you folks on the 2.7 liter. It has good power. But the inside of my tail pipes are solid black. It even turns black on the outside close to the exit of the tip. My plugs foul about once a year. when I take the plugs out they are covered in a dark oily liquid. Its not oil, it appears to be carbon built up on unburnt gas. I also get about 17mpg. Could anyone tell me what could cause this?


thanks

Beartracker

You don't say how old or how many miles you have but have you replaced the A/S sensor ? I'm talking about the one on your manifold between the engine and muffler. This sensor monitors your air/fuel mixture and if not working right can cause the problems you are describing. It should be done every 70,000 miles. It sounds like you may have bad valves or a good chance at bad injectors. Mike

crazy_horse3030

the truck has 118025 original miles. I have replaced that particular sensor because it went out at about 90,000 miles. The truck is a 1998 model. It doesnt burn a drop of oil. Has alot of power. It just seems to be running awful rich.

MTL_4runner

You might try a Seafoam treatment.....
https://www.yotatech.com/forums/f123/seafoam-injector-intake-cleaner-good-stuff-64836/

Are all the plugs black? any pics?

mkgarrison5

if it were my truck i would do a major tune up.

fuel fitler
plugs
seafoam (follow MTL's advice)
maybe even clean out the air intake part also.

i would do this just to see what kind of difference it makes. all together about 30$ worth of parts.. take that back maybe a little more for the fuel filter

crazy_horse3030

I changed the plug wires, put in new plugs about 3 times. New air filter. New fuel filter. None of that really worked.

I dont have any pictures of the old spark plugs, but they go bad about once a year. they are solid black on the prong.

So the seafoam might do the trick? Can i d/c the vaccum going into the pcv valve and pull it in from there?

thanks