New 02 sensor possibly bad?

[SHOByrds]

I had the code 172 so I changed my 02s. Now i have 172 176 and 136. I cleaned the MAF and changed a couple of vacuum hoses that looked dry rotted. I dont think i can check the other vacuum hoses unless i pull the intake mani off. SO is it possible that the brand new 02 sensors have gone bad?

I need a solution its driving me nuts....i drive my 92 about 75 miles every weekday!

 

[rubydist]

both sides lean is likely a vacuum leak or a bad mafs - if the mafs is dirty and reads low it will result in lean codes too.

 

[SHOByrds]

I have put about 600 miles on it since i changed the 02 sensors....would this cause the sensors to ruin?

 

[kevinspann]

Exhaust leaks? Y-pipe fully seated? Could be that, or you have a vacuum leak.

Did you disconnect the battery and reset the keep alive memory?

 

[SHOByrds]

It seems like I reset the battery just about every week...i just replaced the starter and there is always something to fix week to week.
How would i find exhaust leaks or if the y pipe is fully seated?

 

[rubydist]

if the Y pipe is not fully seated, it will have an obvious exhaust pop from the leak being so close to the valves. exhaust leaks after the 02 sensor can also cause erroneous readings, and leaks that close to the engine almost always result in a 'tick' sound, so you can typically find them pretty easy.

the 02 sensors are not going to be damaged in 600 miles of reading lean, but you want to get that fixed to avoid engine damage and get the mileage up to where it should be.

 

[SHOByrds]

I found a leak in a vacuum hose but it seems like il have to take the intake mani off to replace it. I don't think i can fit my hands under the runners connecting to the intake.
Is it possible without taking the Manifold off?
And im guessing il need new intake gaskets if i do or can i reuse them?

 

[rubydist]

you can re-use the intake gaskets.

while you have intake off, replace valve cover gaskets unless you know they are pretty new, and check valve lash while at it.

 

[SHOByrds]

Thanks.
I replaced the valve cover gaskets about 30k miles ago.
Is there a write up on checking valve lash?

One more stupid Q Can i get a vacuum hose set or do i just buy it by the foot at the auto store?

 

[kevinspann]

Manifold is pretty easy to remove on an MTX. You would be best off to just buy vacuum hose by the foot. shophoenixproject.com had a write up, but the site is currently down. I'm sure there is one somewhere here.

 

[rubydist]

valve clearance is easy to measure - all you need is a flat feeler gauge set.

intake .006-.010"
exhaust .010-.014"
the lobe must be at least 90 degrees away from the lifter when measuring.

you also need to make sure there is no wear or roughness on the shim - that can wear off the lobe if it exists.

 

[SHOByrds]

Ok thanks