Yesterday when I was driving the car I came to a stoplight before it had completely warmed up and it shook while idling. Once I got moving it didn't shake anymore and didn't shake again until today. I started driving before it was completely warm and this time it was shaking under normal acceleration. When I came up to a stoplight it still shook and the exhaust was popping too. No pattern to it, just kinda popped here and there. It was idling lower than usual probably about 600-700rpm or so then it surged up to about 1100rpm and the check engine light came on. The prompted me to check for a trouble code and the scanmaster read dtc 44.

I pulled over into a parking lot and checked the all the readings at idle. I didn't have anything to write with so I'm going from memory here:

MAF - 6 (normal for my car)
SP - 40 (usually 20-22. It seemed to slowly go from 40 to 30's to 20's then back up to 40 for a while)
LP - 4.0 (usually ~1.3 It did the same thing the SP did, sometimes slowly move down then go back up slowly and stay)
rP - 1.3
dtc - 44 (O2 sensor lean. Could be bad sensor, wires, vacuum leak, low fuel pressure)
LBL - 160
rBL - 108 (while driving, these would do the same thing the LP and SP did above, move slowly toward equalizing then go to crap again)
CEL - 16 (under my *extremely* light acceleration on the way home I noticed CEL 18 while cycling through the readings)
Lin - 122 or 136 and it did not move at all
rin - can't remember the number, but it didn't move
O2L - it was either up between 800-900 or between 100-200 and didn't bounce between any other numbers. Not the usual 100-900 range.
O2r - it was either between 400-500 or 200-300 and didn't bounce between any other numbers just like O2L
IAC - 70 (usually 40)
MAP - 8.7 (usually 9.0)

So there they are. While sitting there at idle, it shook and popped like before. I didn't see, smell or hear anything different under the hood or inside the car. The exhaust smelled extremely rich, or maybe it was oily I can't quite distinguish, like a lawnmower.

Once the car warmed up the symptoms were the same. SES would go off and come on. The readings wouldn't go back to normal with it off but they did improve slightly. Please help, this is my dd! (odometer just hit 198,000 miles btw)

 

Just watched it idle for about 15 minutes. It seemed to start having problems once it warmed up. The numbers would quickly get as bad as mentioned above. It would shake, the exhaust would pop occasionally. I noticed a few things, the pen I had ran out of ink so going from memory again here:

The IAC was higher this time, at 49. The MAP was higher too, at 10.4. The O2L was bouncing around from 100-900 like normal, sometimes staying high, but not like before. O2r was low, either between 100-200 or 200-300. Not 100-300. If I tried increasing rmp's, all readings would get worse and stay that way. It gave a couple good pop's when I let off the gas from 2000rpm too. Once the engine surged 100rpm's or so and the SES light went off but the readings didn't change. After a few minutes they went back to normal and the car felt and smelled like it was running fine. After a few more minutes it went to crap again. Look out the windshield with the hood up I could see heat coming off the engine and even smelled a little coolant when I went to take a look but the engine temp never got above 190*

 

I swapped O2 sensors to see if the readings would swap along with them. When I pulled the passenger O2, it looked brand new, totally clean. When I pulled the driver O2, it was black. When I started it with the O2's swapped, the passenger side varied from 100-900 and the driver side wouldn't go above 300 and didn't move around. There were pops coming from the driver's side header while it was idling. All the other scanmaster readings were the same. The driver's side was maxed out at 160, and while it was idling, it did another one of its small surges and the passenger side is now maxed out at 160 and I have a dtc 64 with the 44. I replaced the driver's O2 (the one that was clean and originally from the passenger side) with a brand new O2 and nothing changed. The readings don't vary.

So now both banks are maxed at 160. Why didn't the new O2 change anything? Is it possible my luck is horrible and I bought a bad O2? I suppose it could be the wire, I'll check that with the voltmeter.

I took out the PCM BAT fuse to clear it and I'll see what happens after about 20 minutes. This sucks.

 

After starting with the PCM reset, O2L is reading 003 and O2r varies between 0-100. The exhaust is still smelling rich and the oil kinda smells like gas too I suppose. There isn't any smoke or anything. That's all for today, I'm taking it to a shop.

 

Let us know what they find out!

 

As I drove it this morning, it started misfiring as it warmed up and presenting the usual symptoms. This time rBL was at 160 and LBL was at 108. All readings were the same as the first set except right and left are now reversed.

 

Just tested the O2 wires. Both had the same readings:

Gray: 1.56v
Black: 0.0v
White: 0.0v
White: 12.53v

I'm going off the colors on the sensor itself, not the wire it plugs into since those are too dirty to tell. Are these normal?

I'm checking the gounds.

 

My car ran perfectly for the mechanic. While I drove my buddy home and then myself home, it ran perfectly. The mechanic couldn't tell me what was wrong. This obviously was an intricate and painfully detailed plan by my car to give me the most infuriating April fools joke ever.