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/P Sensor, O2 Sensor, Fuel Cap Pressure, Fuel Pressure Regulator, Fuel Pump, Cracks in manifold...

 

[tdoggs01v6]

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.

i had those same ones flashing when my egr port was clogged...unclogged it and fixed the problem....not really sure if that would help you any tho

 

[001Stunna]

Some more info...when the code came up this was the freeze fram data this time. Any1 that can sort of dumb this down for moi lol...

P0171 - System too lean (Bank 1) ...even though bank 1 o2 sensor got changed already
Fuel Sys 1----CL
Fuel Sys 2----CL Fault
Calc Load%---63.92
ECT *C--------90
STFT B1%-----17.19

 

[Roadrashvtec]

Had the same problem and it ended up being my Fuel Pressure Regulator.

 

[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

 

[BlkCurrantKord]

Yea the bosch ones don't last long, kinda like their plugs.

 

[001Stunna]

Yea the bosch ones don't last long, kinda like their plugs.

Arghh...alright well last question before i make an order to get some parts in lol...the engine on a 99 Accord LX (vtec) would be F23A1 correct? and this would be the non-California model? I think im right 99.9% but gotta make sure lol...

 

[finch13]

F23A1 is the VTEC non-ULEV.

Do you have a Bosch sensor in there now? I'd replace that with a Denso one first and see if the CEL goes away. There's not a lot controlling the A/F mixture besides the primary O2 sensor and some EGR stuff.

 

[001Stunna]

F23A1 is the VTEC non-ULEV.

Do you have a Bosch sensor in there now? I'd replace that with a Denso one first and see if the CEL goes away. There's not a lot controlling the A/F mixture besides the primary O2 sensor and some EGR stuff.

Well what happend is... I usually go to a mechanic close by for oil changes etc and always go up to another "better" mechanic a lil farther away when it comes to getting things done. I made a trip to buffalo this weekend though and the BETTER mechanic wasn't available due to moving shops etc and i had to resort to getting the "oil change" mechanic to fix the problem. I left the car with him as i had work and when i went to pick it up he said it was fixed...and i got charged a hefty $350 CAD. I thought he replaced both sensors only to find out on my trip to buffalo that he replaced the one on the cat onlyyy(with a bosch sensor)...and the CEL still came up clealry saying BANK 1. So now im planning on getting both front/back denso sensors and getting the bastard to put them on and hopefully receiving some sort of refund and finallyyyyy never going to him for anything buy oil changes.

 

[finch13]

The secondary sensor only monitors the catalytic function, not A/F mixtures. Take it back to that retard and ask for a refund or for him to fix the problem.