PCV valve change on 3.0 V6

[dguest]

Hey guys, new to the site and fairly new to 4runners only had mine 2 years. I have a 93 with a 3.0 V6 and I have a few questions:

She's been running like crap lately, at first it was lagging a bit when I tried to accelerate, I had recently almost run out of gas and so I thought maybe I clogged up my fuel filter so I changed that... no change.

Then I thought I wasn't getting enough air, so checked the air filter, not clean but not in bad shape either. had a buddy replace mass air flow sensor cleaned up the throttle body. Checked all vacuum hoses lines etc. all was good.

Replaced spark plugs/rotor/cap/lead set.

Problem is getting worse. Thinking it may be PCV valve, I am burning more oil than usual (no leaks) truck runs great when I floor it but doesn't like running between 1000 to 2500-3000 rpms and sometimes it idles really rough too.

I was told I had to remove plenum to replace pcv valve, is this true?

Any suggestions?

Thanks for the help!

 

[purevenom1]

It is a PITA. I went ahead and did mine when I did the valve cover gaskets. Have to remove plenum unless someone has found a shortcut to get it out and back in.

 

[bigbsvo]

Yes, your best bet it to remove the plenum. And if you have oil leaking from the valve covers you might as well do them both, even if you don't have oil leaking do them anyways.

 

[4running1990]

if you do decide on removing the plenum to do the valve cover gaskets to check to see if the pcv valve is bad shake it if it rattles its good if not replace it along with the gasket around it

 

[bigbsvo]

Rattle or no rattle

if you do decide on removing the plenum to do the valve cover gaskets to check to see if the pcv valve is bad shake it if it rattles its good if not replace it along with the gasket around it

Honestly, if your going to go to the hours of trouble to r&r the plenum replace the pcv valve regardless if it rattles or not. It's a lot of work to remove it and I certainly wouldn't stick the old one back in just because it rattles. think about it.

I've been a tech for 25 years and can't remember the last time I had to replace a pcv valve for a drive-ability problem, or even an excessive oil consumption problem. It's very rare to find one that gives issues. But, I guess they do, from time to time, but not in my lifetime. LOL ;-)

 

[4running1990]

Honestly, if your going to go to the hours of trouble to r&r the plenum replace the pcv valve regardless if it rattles or not. It's a lot of work to remove it and I certainly wouldn't stick the old one back in just because it rattles. think about it.

I've been a tech for 25 years and can't remember the last time I had to replace a pcv valve for a drive-ability problem, or even an excessive oil consumption problem. It's very rare to find one that gives issues. But, I guess they do, from time to time, but not in my lifetime. LOL ;-)

i know i was just saying if he wanted to diagnose the problem that it is the pcv valve he sould check bc it could be something else

 

[purevenom1]

How did the plugs look when they were changed? Rings could be bad on the pistons causing an oil leak and your burning it that away. That could be causing it to load up at a lower rpms. Most of the time when the PVC fails you end up blowing a seal or gaskets due to build up of pressure not able to escape. Did you change the plug wires. Could be having a misfire. Have the truck running and mist water over the wires when it dark out to see if its arcing across. If so you will see little lighting bolts.

 

[dguest]

The plugs looked ok but the a$$ H*&e that had it before me put in the wrong plugs, and yeah wires were changed too.

Hope it's not piston rings, I can't imagine it's something big it IS a 93 but there is only 180000km on it and only 50k were put on by me.

It doens't have any trouble when I tramp the peddle down, it takes right off, just doesn't like running at the same speed when the rpms are under 3000. It gears down fine when I get to a hill but the the engine won't respond so the down shifting just slows me down even more! then it gears down again and I have to take my foot off the gas or she takes off again.

 

[sugarshack]

sounds fuel starved. have you checked the pressure? could have sucked some crap into the actual sending unit/filter. EGR valve will do the same sometimes if it is failing. at an idle, you can play with the diaphragm and see if it gets worse or clears up for a second. i would replace the plenum gasket itself if you go that route. getting it off isnt the nightmare everybody claims it to be, but it is about a skill-level 3. if all your hoses still have #'s on them, make sure you mark where they go back, or you will never get it back together. i would highly recommend replacing the valve cover gaskets while you are in there. (you dont want to go in there twice)i would also replace the bolts for the valve covers, the old ones are notorious for breaking off. i cant imagine it is the pcv but stranger things have happened. oil consumption fits the bill. you dont have oil in your coolant do you? if by chance the head gasket is barely blown...

 

[SwiftRunner]

Honestly, if your going to go to the hours of trouble to r&r the plenum replace the pcv valve regardless if it rattles or not. It's a lot of work to remove it and I certainly wouldn't stick the old one back in just because it rattles. think about it.

I've been a tech for 25 years and can't remember the last time I had to replace a pcv valve for a drive-ability problem, or even an excessive oil consumption problem. It's very rare to find one that gives issues. But, I guess they do, from time to time, but not in my lifetime. LOL ;-)

I've replaced a number of PCV valves on various vehicles I have owned. However, if you do have one that is stuck you can clear it with Carb cleaner. When I found out where it was on my 4runner, I was shocked. Most journals recommend changing it out every 30K miles, but removing the Plenum to do it seems rather insane to me.

 

[Staceman]

3 letters...
TPS

 

[SUBTEGRAL]

The Chilton's repair manual says the 3VZ-E 3.0L V6 has no PCV valve but instead uses "orifices" to ventilate the crankcase. I've read this in that manual more than once. ... So I figured this was why I could never find mine.

Is the Chilton's repair manual wrong?

 

[Rix]

The Chilton's repair manual says the 3VZ-E 3.0L V6 has no PCV valve but instead uses "orifices" to ventilate the crankcase. I've read this in that manual more than once. ... So I figured this was why I could never find mine.

Is the Chilton's repair manual wrong?

Yes its wrong. Chiltons and haynes and those are crap.
Long 45 degree needle now pliers can get under there to get the pcv valve out.

 

[SUBTEGRAL]

Damn it .. I was hoping the Chilton's manual was right.

As for the Haynes manual, it only talks about the PCV valve for a 22R-E and mentions absolutely nothing on the subject of the PCV for the 3VZ-E. :|

 

[Rix]

Damn it .. I was hoping the Chilton's manual was right.

As for the Haynes manual, it only talks about the PCV valve for a 22R-E and mentions absolutely nothing on the subject of the PCV for the 3VZ-E. :|

I'd call that a fail......

 

[imagemaker]

Im having a similar issue. 2000 4runner 3.4 motor. Replaced air box,(potential stripped screw on the MAS) replaced MAS, Replaced TPS, replaced IAC, Replaced ECT, Replaced brake booster ( as per Dealer diagnosis) , checked vacuum lines for breaks. New plugs. No codes. Been to 4 shops, all the incorrect diagnosis. The problem is exactly the same and has not presented itself differently after each repair.
Runs fine on start up. As it approaches normal operating Temp, it will seem to lose power. If you come to a stop and accelerate it bogs down, back fires through the air box. Does the same thing if restarted after 30 minutes. When the issue occurs , if you pull over and restart the vehicle it will return to normal operation. Love to hear if you finally resolved!

 

[4sports]

going to attempt 3.0 PCV replacement today. Hoping I can reach in without removing the intake plenum.

 

[89FourRunner]

going to attempt 3.0 PCV replacement today. Hoping I can reach in without removing the intake plenum.

You can, I did. Did not remove plenum or anything. Just need a pair of long needle nose pliers with a 90 degree end.

Take your time and do gentle twists back and forth. Hit it with some penetrating oil if you can.

 

[4sports]

It was getting dark, and I didnt get the job done. What I did instead was spray carb cleaner down the PCV tube in an attempt to clean it out, for now. Seemed to help actually. I have cleaned metal PCV valves on other cars this way with success, and so this was the thinking as a short term fix. I would think the only danger would be thinning out your engine oil if you sprayed too much.

 

[fastgtfairlane]

ive been having some drivability issues similar to yours. yesterday i did finally change the plugs and damn they were in bad shape! i also found a few vacuum leaks from cracked vacuum hoses. also replaced the fuel filter. ive also read that cracks in the intake hose form the filter and air meter can cause stumbling like mentioned. after replacing the plugs, fuel filter, cleaning the k&n filter and replacing the dry rotted cracked vacuum lines, my runner seems to be running much better. so might want to check for any dry rotted and cracked vacuum lines. it will surely cause stumbling and poor fuel mileage.