Kia Optima 2001 P0171 system too lean bank 1

Okay, so I tried to look around under the forum for a similar enough situation but couldn't find anything to post on. So I have decided to start this thread in hopes that someone can please help me keep my sanity, and keep me from being even more broke and carless.

My problem is with my Kia optima 2001 SE 4 cylinder 2.4L. It has had problems up to wahzoo ever since I bought it, but they were far enough apart and just within my budget that i've kept the car. Now, I can't afford a new car, and I have put way too much money into this car to get anything close back out of it, so I would like to try to keep it another 2-3 years if possible. I am having a physical issue that may or may not coordinate with my trouble code. I receive a P0171 code almost every day if not multiple times a day. It didn't start that way, it used to be once a week, now its more frequent (it seems). Also, the code often resets itself which I am not exactly sure what that can mean. Anyhow, that is the code, the physical issue I am having with my car (besides the presence of the lean) is that it often times has little jerks while driivng, and will raise in RPM but not speed, and then eventually jerk to catch up. It doesn't have issues shifting gears, but the jerks are becoming more common. I have replaced the upstream O2 (on the recommendation of a mechanic), it didn't seem to do anything, I also just recently replaced the MAF sensor myself from a wesbite called A1, it was really cheap compared to the kia part, so i am wondering if it was a mistake to order cheaper? I installed it, the car initially is seeming to have the same issues, but I will update in a day or two since I just put it in last night. Last year I also had all the coils and plugs replaced because a coil went bad and ruined them all. So those should all be okay (I would hope). Any other information or help would be so greatly appreciated. please comment if you need more info, I will check daily to update. Thanks so much!

Ken

There may not be a specific thread for that code on that car but it's a pretty generic and common code for all makes and models and they all have similar failures that lead to it. It's not all that difficult a dtc to diagnose if it's as common as it is on your vehicle. Off the top of my head I can't remember any pattern failures for that dtc on Kia's but I'd imagine it's either a vaccum leak or maybe a fuel pressure issue although often low fuel pressure leads to starting issues which you didn't state you were suffering. Your mechanic that told you to change the 02 sensor is clueless and not worth your money or time. I'd suggest taking it to the dealer because those techs will have the most expereince on your car and obviously your mechanic isn't too competent or too interestted in doing diagnostic work or he would have done more testing instead of telling you to "throw an O2 at it"! Too many people think the dealer will be more expensive but they have the most expereince with your model of car most of the time which is nothing else can increase the odds they guess correctly vs someone who never works on a Kia! Money spent on unneccessary parts and labour is no savings compared to paying a dealer a little more to hook a factory scan tool to it, Search factory TSB's and
probably get it right sooner if not the first time!

Jeff,

Thank you very much for the reply. I didn't mention this, but over the course of the 2 years of having this car, I have seen 5 different mechanics for the same jerking issue. Only in the last few months has the loss of RPMs really been apparent, and in that time is when I have had three different mechanics diagnose it. I totally agree with you, all three of them were not very "into" the diagnosis, and one of them was a KIA dealer mechanic. the other had worked for Hyundai (kia) and 2 of the three were in their later years and had apparently been working on cars for many years. I wish I could find a 100% competent mechanic around here to throw a few hundred dollars at and either quickly figure out if it's a vacuum leak or not. Everyone seems to think so, yet none of them found any, except one, who replaced the PCV valve. I am just at a loss, and I have just a little money left, and can even change my own O2 sensor for 50-100 dollars. I only am curious about the O2 sensor, because this site lists the code's common issue as vaccum or o2 sensor related. I don't think it is anything with the fuel pressure, since like you said, there are no other symptoms commonly related. I know it is either a vacuum leak that is troublesome to pinpoint, or the tranny slipping or possibly plugs/wires/coils but those have been replaced recently, (at least the plugs and coils have). When they replace coils and plugs, do they tend to replace the wires and stuff as well? Should I have a mechanic go at it and really try to find a vacuum leak? I just don't know what to do =(. Thanks again.

Ken

Yeah but you took it to the dealer for a jerking issue but was the code there at the time? if the code is staying active now is the time to get to the bottom of it. My second leg of advice is find 1 mechanic and stick with it and don't expect it to always be diagnosed in and hor or less! too many people drive in and expect the magic machine to tell them what part to change and if it requires any further diag then that they they feel they're being ripped off. You r ripping yourself off by always going for the min diag charge becasue it puts you and the tech behind the gun and under the clock, if Im given 1 hr to diagnose something at the dealer that's what you get 1 hr, no promises no gurantees nothing! If you give me the car and say fix it I agree and you agree to see it through. It doesn't give any tech authorization to start throwing parts at it. I'd get it back to the dealer, if you want a different KIA dealer but leave tit with them until they can tell you what it isn't aand with better certainty what it is! If the code's active you should have fuel trims that are all out of whack and this should leave the tech if competent to better diagnosis