I have a 2000 Nissan Sentra XE 75k miles. I have been noticing a problem the past couple of weeks. Whenever I start the car after it's been sitting for a couple hours (after work or in the morning heading to work) it seems to lose almost all power when I attempt to accelerate and then after a few seconds it "catches up" and the RPM's go way up and then it is fine. When it does catch up the car jerks violently and the engine seems to rev up and back down and back up etc for about 5 seconds before it starts funning normally. After that I don't notice any problems while driving. I drive up a huge hill on the way to work about 5 minutes after my house and don't notice any sort of performance problems while climbing that. It's only when the car first starts and is cold. Also, if I let the car warm up for a couple minutes I never have this problem. However, it seems like something that shouldn't be ignored and I would like to find out what the problem is. Any helpful hints or suggestions would be greatly appreciated.
I had the exact same problem in my car and it was an exhaust leak. One of my gaskets had a pinhole leak that I guess would seal after the car was fully warmed up.
I just took it to AutoZone and they hooked it up to the code reading machine and it came back with an error P0171 System Too Lean (Bank 1). Does that sound related to your problem or could it cause the same thing?
with the p0171 code - and I've had one shop tell me it was the Mass Air Flow sensor, but I don't think that's it (I've read that others have had the same problem, replaced the MAF sensor, and still have the problem). I think it might be an oxygen sensor or a similar problem, but don't know much about cars. I've also heard that reprogramming the ECM has solved this problem for someone, too (since there was the recall on the ECM housing that could damage it - the insulation was emitting sulfur, of all things!)
I at first just had the Check Engine light on for a few days then off for a few days for 2 weeks, then it went to having trouble at start-up or after sitting for a several hours. Now I've got a SES light on all the time *and* trouble at start-up!
Anyone else had this problem? If so, what did you do to fix it? I've been searching the internet for a week and seen 5-6 people with the same trouble, but not many answers on how to pinpoint the problem! Thanks!
Last edited by lstrahinic : Oct 9th, 2005 at 10:08 PM.
I just took it to AutoZone and they hooked it up to the code reading machine and it came back with an error P0171 System Too Lean (Bank 1). Does that sound related to your problem or could it cause the same thing?
I never threw a code, and I don't have a manual with me at work so I'm not sure what code that is. It was definetely an exhaust leak on my car, yours may be different.
I never threw a code, and I don't have a manual with me at work so I'm not sure what code that is. It was definetely an exhaust leak on my car, yours may be different.
that code means that the computer is getting information from the upstream oxygens sensor that the vehicle is getting too much air in the mixture, it cant correct it by lengthing injector pulse either, so the un-wanted air is coming from a source where it shouldnt come, a cracked vacuum hose, torn intake gasket, or air being pulled in an exhaust manifold to head gasket or crack in the manifold. Or you could also have low fuel pressure due to a clogged fuel filter or poor fuel pump performance. the oxygen sensor could also be lean biased, but that would be accompanied by the car running extremely rich, puffing out sooty black smoke where the computer is lengthing the injector pulse width.
It sounds like a leak to me.. I know if your using a aftermarket intake and their is a leak their, U would get some results like that, but it could be in your exhaust aswell.
Thanks for the replies all. I am going to take it to a mechanic this weekend and I will pass along this information so hopefully they can find out what's wrong with it.
Take that O/2 out and look at the cat. See if your cat is not falling apart inside. I have seen alot of theses cars cats fail causing this code forst then a P0420 cat efficiency code
Much to my dismay it was the MAF sensor. Initially they just cleaned it because they said it will act up sometimes if it's dirty. However, I got half way home and the symptoms got worse after it was cleaned. I took it back and they replaced the MAF sensor and now it's working fine.
k, that does make sense. sorry i sent you in the wrong direction. the maf was telling the computer that a lower amount of air was intering the engine, so the computer shortened the injector pulse to match what the maf was saying was coming in, when in fact, more air was coming in. therefore there was too much air in the mixture and not enough fuel. i have had that happen a number of times to me. i dont know how this effected the performance of your car when it is first started and cold. every car that has had a mass air flow problem has run crappy at any temp. that is why i thought of the coolant sensor..... oh well, glad you found the problem and it is now resolved...
k, that does make sense. sorry i sent you in the wrong direction. the maf was telling the computer that a lower amount of air was intering the engine, so the computer shortened the injector pulse to match what the maf was saying was coming in, when in fact, more air was coming in. therefore there was too much air in the mixture and not enough fuel. i have had that happen a number of times to me. i dont know how this effected the performance of your car when it is first started and cold. every car that has had a mass air flow problem has run crappy at any temp. that is why i thought of the coolant sensor..... oh well, glad you found the problem and it is now resolved...
No need to apologize, I appreciate the help. We were able to drive the car most of the summer because we couldn't afford to take it to a mechanic but once winter came and it was freezing outside it would barely run at all. I'm not sure why it worked when the car heated up to be honest with you, I thought that was strange as well.
Just a follow up. My car started acting up again after taking it to the mechanic. It seems like it lost almost all power and I was able to drive home but it was slow going. I took it back to the same mechanic as before and they said it has a different error code now. P0302 which means engine mis-fire on the 2nd cylinder. He said that it is a bad fuel injector. I need a professional opinion from somebody if they are trying to rip me off by replacing parts that don't need to be replaced or if this problem seems like it may be a bigger problem. I honestly can't afford to keep taking it back while they replace parts to find out what the "real" problem is. Do these 2 problem together sound related like it could be a different problem? The car worked perfectly for 7 days after having the MAF sensor changed. Now I am having these problems. It seems like they may be related to me but I am not an expert.
get a second opinion, but the misfire can be caused by a bad/clogged injector. Have you replaced the sparkplugs or checked them?
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I've got the same problem...
Linear Mode
