raz Posted October 8, 2006 Report Share Posted October 8, 2006 The check engine soon light came on about 2 weeks ago. I waited a couple of days before i pulled the codes, thought it might had been some bad gas. I am using regular unleaded fuel. The codes i pulled are as follows: PCM P0171 and PCM P0174 I believe these refer to Fuel Trim System Lean Bank 1 and 2. I do not know what these mean or what causes them other than i figured the fuel mixture was lean. I cleared the codes to see if they would appear again. The check engine light went off and the codes have not returned. Now here is the but, i have noticed the idle is rough. It idles at around 7500 RPM with little fluctuation, but you can feel that it is not smooth,rougher than normal. I am open to suggestions. I have not cleaned the throttle body since about a year or two. I am guess it may be a sensor or fuel injectors, maybe the fuel i am using. Thanks , any help in this matter is appreciated. Raz Link to comment Share on other sites More sharing options...
OynxSTS Posted October 8, 2006 Report Share Posted October 8, 2006 It might not be your problem... but are your crank sensors original? Bad crank sensors on 00-03 N*s will cause bad idles, stumbles, stalls and all kinds of odd codes and no codes too. Common problem on 00-03 N*s BTW Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 8, 2006 Report Share Posted October 8, 2006 A common cause of these codes is a dirty air cleaner. If they came on once and the code doesn't repeat, you might have gotten water splashed up into the air intake behind the left headlight somehow and wetted the element. I would change that first, and check and make sure that all the intake hoses are properly on and clamped, and the air cleaner housing is securely inserted into the hole in the fender on top of the PCM. Another problem that can cause these things is the fuel pressure regulator (FPR). I would check it next; you pop off the engine cover and pull the vaccum hose off of it and sniff it; if you smell gas, it's bad. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Ranger Posted October 8, 2006 Report Share Posted October 8, 2006 A leaky FPR would cause a rich condition. Likewise, I would not expect an air filter to cause a lean condition. Crank sensors will usually cause the car to die, but will usually restart. I'd look for a vacuum leak on a lean condition. Link to comment Share on other sites More sharing options...
raz Posted October 8, 2006 Author Report Share Posted October 8, 2006 I have had the crank sensors replaced twice. I am pretty familar with those issues. The car runs great ,no miss etc.. My wife and i just both noticed the rough idle. I will check for vacuum leaks, sensor connections and air filter etc. tomorrow. I keep waiting for more codes, but all clear. Link to comment Share on other sites More sharing options...
OynxSTS Posted October 8, 2006 Report Share Posted October 8, 2006 How many miles? time for new plugs? Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
Ranger Posted October 8, 2006 Report Share Posted October 8, 2006 It idles at around 7500 RPM with little fluctuation, I assume (hope) you mean 750 RPM. 650 is normal so it's not too high. Again, a vacuum leak woud cause that as well. Link to comment Share on other sites More sharing options...
raz Posted October 8, 2006 Author Report Share Posted October 8, 2006 Sorry , I mean 750 RPM. The mileage is only 61,000. Link to comment Share on other sites More sharing options...
OynxSTS Posted October 8, 2006 Report Share Posted October 8, 2006 based on what we know I agree with ranger... vacuum leak... Maybe leaky egr... But I'll bet vacuum Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
raz Posted October 8, 2006 Author Report Share Posted October 8, 2006 I took top cover off engine and i checked for vacuum hose problems. Everything looked ok that i know of. The PCV grommet was not sealing real good, kind of loose. Link to comment Share on other sites More sharing options...
Logan Posted October 11, 2006 Report Share Posted October 11, 2006 There is a large, 1 inch wide rubber boot....in between the intake and throttle body. Mine cracked on the bottom. You have to remove the intake to replace. See #2 in picture. Logan Diagnostic LLC www.airbagcrash.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
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