WoW....this is a lot of info to digest!

To recap. I swapped out the 02 sensor because I got the error code P0130 once for it
back in May. Cleared it and everything was fine. Then I noticed that I was burning too much gas so I figured I better replace that sensor.
Also there is a nasty leak in the muffler. Along the seam in the bottom. I patched it up with JB Weld and it held for a time. But It fell out! Can that leak be effecting anything here?

BTW I did add some oil. And I did notice the dip stick wasn't seated properly. Didn't think much of it at the time. I'm going to double check the oil level. Make sure I didn't over fill it.
The MAS sensor is way back in right next to the throttle body. PITA to get to in a van! The screws look rather crusty too!
Then check for vacuum leaks. As far as a wiring problem goes, I can look for frays and such. But I'm not confident I will find any problems there

I think its weird that the values jump around so much so quickly.

 

NAPA sells a muffler patch kit to make some muffler repairs, check it out..

Do you have a volt or multi meter to use ?

 

Yes I have an AmpProbe multi tester.

 

On your o2 sensors the upstream are they narrowband or wideband?
If wideband your O2SB2S1 is actually good with a close to zero mA reading. We go by volt not mA so I didn't catch that previously.

 

Update:
The first thing I did was check the oil. Like I said before the last time the dip stick wasn't in all the way. And guess what...same thing again. So I check the oil level and replace the stick. But this time I made sure to get in all the way. In the Van the stick is well hidden in behind the air breather and is hard to get at. So the oil level was right at the top. OK cool right. But when I replaced the stick this time and making sure it was in there right it went in even further! So I pulled it and the oil level was right at the max line.
So the van was almost out of gas and to take any readings it needs to be warmed up so I decided to run to the gas station and take the reading when I got back. While driving I decided to clear the codes. They check engine light hasn't been back on after a 60 km drive. WTH?

 

Ya gotta know when ya got it good , lol.

Now you might have a better idea of what to check, next time the C/E light comes on, you at least have some idea where to start checking.

 

Well...it's a sad day. I drove the van again tonight. Parked in town and when I left the friggin light came back on. 75 kms

I was too good to be true. I'm left wondering if I should drain a little oil out get it down to where it should be. The engine could be sucking up the excess and burning it?

 

When the light comes on, you start each check out with the same procedure.

See what code you have, try to learn what causes them and go from there. It doesn't have to be the same problem, things do change.

Does that check eng lamp always come on at start up or what other times or conditions? That info is important to know.

 

The engine light seemed to come on shortly after start up. I wasn't watching for it but I noticed it within a minute of leaving the parking lot.

 

What code is in the computer now ?