car-whore

Well, I finally got around to changing out my leaking valve covers on my 00' 4runner. While torquing down the bolts, my friend cracked my valve cover so I actually had to do the job twice....

After putting everything back together, I'm having some problems with my truck which seem to be emissions related. Basically, my 4runner runs absolutely perfect up to about 60mph. At 60mph, the engine starts to vibrate and the faster you go, the more it does it.

I was initially throwing 2 codes which were both P0171 - System too lean. I replaced the MAF and I'm now throwing only one P0171 code. I was pretty diligent about making sure all the vacuum lines were reinstalled and I checked to see if I missed any lines but didnt see anything.

I really need to get this thing fixed and I'd really appreciate it if somebody who has had experience with this issue can chime in and give me some help.

Thanks guys....Michael

vital22re

iTrader: (2)

how were the gaskets for the intake?

car-whore

They didn't look bad. The vehicle has 263k miles. They're metal and I figured I would reuse them. I was kind of thinking that it might be a good idea to change them....what do you think?

car-whore

I'm willing to try anything at this point, I can't find any spare hoses...everything looks good...just doesn't run right

vital22re

iTrader: (2)

I had the same code during last winter but it went away after trying 2 different MAF's. Check your air intake for cracks. I will be replacing all of my intake gaskets before it gets too cold out.

car-whore

I just replaced the MAF with a factory toyota part....seems to be working like it should.

I've ordered a K and N intake system, I'm tired of the stock intake. It just annoys me looking at it because it just seems so pointless.

I'm going to install the new air intake and then see where I stand. If it doesn't fix the problem, I'm going to get new intake gaskets, pull everything apart (again), replace the gaskets, and make sure I'm not missing anything.

Thanks for your help!

oddjob1370

I was told that intake gaskets need to be changed out everytime you take the intake manifold apart. Something about it not sealing correctly a second time.

vital22re

iTrader: (2)

return the k&n intake. Buy a AFE dry flow filter and do the ISR mod. The oiled filters will only gum up your MAF sensor

4x4climber

true dat. go AFE! ^^^ double/triple check every vacuum line and every plug before buying more parts. And... yes, your intake gaskets may be a bit of a problem. If you did not replace them that could be your whole problem. Always replace gaskets you remove. Keeps you from doing it twice.

car-whore

Thanks for all the help guys!

I will return the K&N and go the AFE route.

Any suggestions on which intake manifold gasket kit to go with and where to find the best deal? I didn't realize they were close to $100 for an aftermarket gasket set.....

car-whore

Also, if someone knows what the intake manifold bolts should be torqued to, that would be helpful information. I'm going to make sure absolutely everything is right this time around. Thanks!

rworegon

5Vz-fe engine?

Does page EG-59, step 17 help you out?
http://www.ncttora.com/fsm/1996/SIL/...c5v/torspe.pdf

Additional torque values:
http://www.ncttora.com/fsm/1996/SIL/...c5v/torspe.pdf

car-whore

Thanks for the info.

Update: I changed out the upper and lower plenum gaskets and I'm still having the same problem. Vehicle is running idling rough and still has the vibration issue. My intuition tells me it has something to do with the ignition system. I recently changed out the plugs and wires but have never changed out any of the coil packs. Is this a logical next step? Again, any help is appreciated!

Does anyone have the link to the service manual handy that they can share as well...........