Contour Enthusiasts Group Archives Forums General Troubleshooting annoying CHeck engine light..

so recently my check engine light came on. so i went to auto zone and plugged in my car. they said that it was either my injectors or my camshaft position sensor. i used this seafoam injector cleaner, and i changed my sensor. the check engine light turned off for about 2 days now its back on. im curious as to what i do next.. heres what the computer said:

P0174 - Bank 2
P0171 - Bank 1 something about running to lean.

(p.s. i recently did the throttle hang fix, could it be something to do with this?)

(p.s.s. i changed my 02 sensor not even 1 year ago)

(p.s.s.s. car seems to run perfect still.)

im curious what to do?!!

- shaun

--98 Silver CSVT DOHC HO, 130,000mi and still runs perfect!!--

If you have both the P0171 and P0174, it could be a massive vacuum leak. Check the worm clamps where you took out the hoses to do the TH fix. Also try spraying carb cleaner to suspected areas (gaskets, joints, etc). If the idle changes, you found your leak.

Also clean the MAF sensor.


MAF sensor cleaning

http://www.contour.org/mods/mods.php?s=howto&displayid=36
and
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=zetecmaint&Number=989728&page=&view=&sb=5&o=&fpart=1&vc=1
and
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1b/cb/25/0900823d801bcb25.jsp

Per TSB,
P0171 - System Too Lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The code is set when the adaptive fuel tables reach a rich calibrated limit.

Fuel System:
�· Contaminated fuel injectors
�· Low fuel pressure or running out of fuel (fuel pump, filter, fuel supply line restrictions)
�· Vapor recovery system (VMV)

Induction System:
�· MAF contamination
�· Air leaks between the MAF and throttle body
�· Vacuum leaks
�· PCV system concern
�· Improperly seated engine oil dipstick

EGR System:
�· Leaking gasket
�· Stuck EGR valve
�· Leaking diaphragm or EVR

Base Engine:
�· Exhaust leaks before or near the HO2S
�· Secondary air concern
Powertrain Control System:
�· PCM concern

P0174 - System Too Lean (Bank 2) Same as DTC P0171, but Bank 2. See Possible Causes for DTC P0171

It's almost always a vacuum leak.

Do check those hoses Tony mentioned. Also, check the PCV valve and the hose it seats into.

Many times, it's the intake gaskets. A cleaning with new gaskets is the cure for that.

Steve

thanks for all the help!