My 00 TL tripped a code on saturday. went to acura, found code p0171 - excessive lean condition. Tech told me it could be a vacuum leak, TPS, EGR, bla bla. Everything turned out ok. He said i could possibly need valve adjustment, which i think is not necessary. I have 130k on the car, but always had premium fuel and what not. So i asked him if it could have been an O2 or bad gas. The o2 was fluctuating fine, a little jagged, but going from 0-1 no problem. He said it could be the gas, so i put a full new tank with some octane booster, and changed the plugs (i hadnt done them yet). cleared the code, and after 5 miles, just came back on. anyone else encounter this and what fixed it??? i did a search, but no real answer.

thanks for the help.
-niko

 

also noticed when at idle, and i floor it, it hesitates and misfires. had that problem before on my eclipse, but it was the wires arching out. im almost out of ideas.

 

I am having the same problem here. What did you do to fix it. I tried octane booster and reset of the ECU, but the P0171 keep coming back. The car is little hesitate at time but otherwise running normal. I suspect I will get a o2 code if is a bad o2 sensor. The only think I can't check is vacuum leak, I guess that I need to go to the dealer. Thanks in advance for any help!

 

Check for a vacuum leak. It could also be a O2 sensor, or need a valve adjustment. It wouldnt have to throw a code to be bad. It could be miss reading causing the ECU to trim too much causing it to go lean.

 

maybe it could be a faulty coil pack.....

 

mine hesitates and misfires in D5 gear ... but not in D4.... it's just weird no Check engine light:S.....

 

That doesn't sound possible, in this case the PCM doesn't care what drive mode (d4/d5) you have it in until it comes time to shift to a higher gear.

This doesn't apply to niko, only vannakam:

Back in the day under heavy acceleration in 1st or 2nd, I would hear what I thought was a lot of misfiring or knocking. I came to realize later on that I was low on oil and that my VTEC wasn't getting enough oil pressure to engage properly (rapid turning on/off of VTEC). Only happened in the 1st and 2nd gears where there is enough acceleration to throw the oil far enough towards the rear of the car to starve the pickup tube to the oil pump. Then again, I was very low on oil. What I explained might not make sense to everyone, but its know to happen regularly on Integra's with low oil, and it proved to be the problem in my case as well.

 

needs valve adjustment.

 

x2 on the valve adjustment. premium fuel has nothign to do with you needing one. have you dont your 105k service?

 

Sorry but I do not see the relation between valve adjustment and engine 's running lean ????

 

if the valves are to tight, that means that the valves open sooner and lets in to much air . causing a lean code.the only other thing are injectors.not spay right.

 

A dirty or partially blocked injectors make more senes to me . The only situation when engine is running lean is not enough fuel to the combustion .

Seafoam and see if the lean condition is gone .

 

id say valve adjustment or vac leak. the intake lead time may be off or entire overlap is off....do u hear any engine knocking? get a long screwdriver, and at idle, listen for it....

does anyone do a smoke test still these days for engine leaks? or...?

 

He is correct. If the valves arent adjusted correctly it can cause a lean symptom.

 

So if valves are mis-adjusted then engine could has a RICH symptom too ,right ?

 

Not as likely as a lean condition