CEL ON...OBD reader stays too lean...

[001Stunna]

Well i took a drive up to Montreal for the long weekend and had some issues come up...Firstly i stopped by 1000 islands(about half way) and when departing for Montreal again the car threw a CEL. I hooked up the OBD reader and it said the car was running too lean. Got to montreal and the whole time there it threw no codes or anything. On the way back today i stopped in kingston and upon starting the car again after a break it again threw a code. I checked it and there it was again "running lean". Whats kind of weirding me out is why does it happen only after a long distance(2-3 hour highway drive) only? The engine temperature was not hot, actually below half and car felt fine...no loss of power anything. I just did a google search on this and found different answers so wandering what you guys think the issue could be...and any solutions =D. I'm just about to go check it again after leaving it for 10 minutes since arrived and see if it throws the code again.
..........
Ok went to check it and it didnt throw the code but on the reader the EV (EVAP Monitor) test wouldnt get completed after quite the time. The Emission Pass Light stays on yellow as well instead of green. I went and pulled the battery terminal for 10 minutes and hooked it up again. Now 4 tests dont complete even after driving for about 30 minutes at all speeds. Tests that are flashing in the video below are Catalyst Monitor, EVAP Monitor, O2 Sensor Monitor, EGR Monitor.
http://www.youtube.com/watch?v=AC1cLxwzmyA

Any info/help is appreciated...as i understand this can mean trouble for the engine running it with no fix.
From reading around ive come with cases where problems have been as MAF Sensor, Vacuum leak downstream of MAF Sensor, O2 Sensor, Fuel Cap Pressure, Fuel Pressure Regulator, Fuel Pump, Cracks in manifold...

[enforcerviper]

O2 sensor is my first guess.

[l69norm]

.... Montreal again the car threw a CEL. I hooked up the OBD reader and it said the car was running too lean. Got to montreal and the whole time there it threw no codes or anything. On the way back today i stopped in kingston and upon starting the car again after a break it again threw a code. I checked it and there it was again "running lean". ...

Post the "freeze frame" information from the ODBII tester the next time this happens. This is the data the computer saved when the CEL was actuated. BTW, pressing the "erase" button on the ODBII tester will clear the CEL. No need to disconnect the battery

[Engi-Nir]

what car?

my corolla had CEL come on for system too lean, and checked it out, it was a common issue with corolla so I just fixed that, and it cleared it instead of fixing the usual 02,etc,(just did MAF)

[001Stunna]

what car?

my corolla had CEL come on for system too lean, and checked it out, it was a common issue with corolla so I just fixed that, and it cleared it instead of fixing the usual 02,etc,(just did MAF)

Car is a 99 Accord LX+ABS

[001Stunna]

One more question since i dont wanna make another thread...When any of you have changed your o2's...has it been by bosch(that stores like CT sell) or Denso / NGK brand??? I was recently told that bosch o2 sensors apparently dont last long

[l69norm]

One more question since i dont wanna make another thread...When any of you have changed your o2's...has it been by bosch(that stores like CT sell) or Denso / NGK brand??? I was recently told that bosch o2 sensors apparently dont last long

I would do some more analysis before randomly changing stuff.

..... Now 4 tests dont complete even after driving for about 30 minutes at all speeds. Tests that are flashing in the video below are Catalyst Monitor, EVAP Monitor, O2 Sensor Monitor, EGR Monitor...

For example, the computer might not be going into "closed loop" operation because of a bad (open) thermostat or it could be a bad engine coolant sensor (i.e. the computer still thinks the engine hasn't warmed up yet)

[Blackjack]

Clean your MAF sensor.

Link for a 04 MAF cleaning/tuneup: http://www.driveaccord.net/forums/sh...ad.php?t=20631