Question about 1998 Mercury Mystique
Barely runs then it catches and rev-es up around 3000 rpm, and then back to barely running, keeps repeating this pattern. Getting trouble codes 171,174,430,1131,1151 Have replaced O2 sensors in last year, plus trouble codes are suggesting lean burn on both banks. I believe its my idle control valve, but would like a little back up before I spend 100.00 Anyone have an opinion
PS: The temp here has been between 0 and -10
The problem is solved, the IAC (idle Air control valve) was the problem. I was glad to be able to bounce this off someone, and get a fast accurate response! Many thanks to Thunder God!!
Posted on Jan 31, 2009
SOURCE: codes #171 & 174
first check out for o2 sensor if its faulty this can show up.but if its proper.Evaporative emission control system leak very small 171 System too lean (bank 1) 174 System too lean (bank 2)
Posted on Jan 05, 2009
2 things to check air leaks from air box tomanifold where it meets at engine check mass air flow sensor and oxygen sensor start with common sense things first
Posted on Apr 16, 2009
9 out of 10 times this is due to a dirty MAF sensor. If you run an aftermarket air intake that uses an "oiled" filter - you greatly increase your chances of this. You can purchase "electronics parts cleaner" from an auto parts store and spray it on the MAF sensor (you'll have to remove any intake tubing to get to it) and clean it. BE VERY CAREFUL to not damage the sensor - don't attempt to wipe it off on the inside, you can damage it beyond repair.
Hope this helps and good luck!
-KC GTO Dad
Posted on Sep 18, 2009
Sounds like you have low fuel supply or a leak in intake system causing lean codes, check fuek pressure and volume first. Cat converter effeciancy could be caused by the lean codes, purge system sounds like solenoid failure, check for high resistance accross purge vent solenoid.
Posted on Mar 08, 2010
SOURCE: running lean on bank 1
P0171 - System Too Lean (Bank 1)
Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.
Note: This DTC is very similar to P0174, and in fact your vehicle may show both codes at the same time.
Symptoms: You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.
Causes: A code P0171 may mean that one or more of the following has happened:
* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
* There could be a vacuum leak downstream of the MAF sensor.
Possible solutions include:
* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect all vacuum and PCV hoses, replace if necessary
* Check for a dirty fuel filter and proper fuel pressure
Posted on Mar 24, 2011
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