I have a stock 2001 Nissan Sentra SE with a K & N Air Filter (cleaned less then 1000 km’s ago). Spark Plugs were changed about a year ago (I believe the wiring was left alone though), as well as a general tune up. Maintenance has been kept up to date on the car as well. The car was recently in a bodyshop being repainted as well.
About 2 months ago, possibly slightly longer, I had gone on about an hour and a half drive, all highway and when getting off the highway, 2 blocks from my destination, my car stalled. No warning light, no check engine, nothing, it just died. I had my music blasting so I did not know the car had stalled/died until I went to turn a corner and found that the power steering was not working, etc. After making the corner I tried to start the car and the RPM went up to about 1500 and then dropped down fast to 0, no hesitation at all, etc and the car of course died. I tried to start the car a few more times and again the same thing. I discovered that as long as I kept my foot on the throttle the car would stay alive and I managed to get it into my parent’s driveway. After a few more attempts with the same result I gave up and let the car sit there for about 10 minutes or so and gave my mechanic a call. While on the phone with him I tried to start the car again and everything was fine. Later on that evening I took the car for another hour to hour and a half drive (mixed highway and city), and the car was fine.
About 3 to 4 weeks ago my car had been displaying similar behavior to an extent but on different levels. For about 3 – 4 days it would start fine but in between shifts it would drop fast and fall below 500 RPM and feel like it was going to stall but then rise again to just under 1000 RPM and by then I was in gear and on the throttle so it was not an issue. I did try this at various times/places by just driving the car down an empty street and then taking it out of gear to see what would happen and again it would drop below 500 and then shoot back up again and seem fine. After those 3 – 4 days everything seemed to go back to normal.
In the last week and a half the car has been doing even odder things. When running errands in and around my neighbourhood I will often have to make short drives, sometimes where I’m just in the store for 15 – 30 minutes. I will come out and start my car and the idle will jump up to about the 1500 RPM mark and then go all the way down to halfway between 0 and 250 RPM (if I had to make a guess I would say about 100 or slightly lower). The car will literally slow down and you can feel it in the engine where it wants to die, the engine get’s very quiet and then it’s like something just picks up and the RPM’s shoot up and then rest at about 900 to 1000 and then go back to it’s usual 750 or so resting RPM.
As I mentioned, this happens when running errands or just when driving to or from work as well. I live about 4 km’s away which takes around 7 – 10 minutes (I know, I should really bike or something but I like to get as much rest and sleep as possible so I take my time). If I get to work and shut off the car and then try to start it again the car will do the same thing. When driving home from work I get the same results.
I’ve had my mechanic scan the car (he is licensed but when doing things for me he is a backyard mechanic located just over 50 km’s away), and there were no codes stored in the memory and at the time he checked it I wasn’t able to reproduce the problem. We did notice that the car was running more lean then rich since we had the computer connected to it and had the graph readout, often times it was staying lean for a long time and he mentioned that the oxygen sensor could be a possibility but did not want to go ahead with replacing it since there could be other factors to the problem. I asked another garage near where I work about it and they were saying it could be a number of different things as well and that they would have to see it while it was happening to figure it out.
Has anyone out there had a similar problem? Any ideas what could be going on or pointers for things to check out?
Another concern I have with all of this is the fact that I have to go and have the emission test done within the next 2 weeks so that I can renew my stick for the car (also within the next 2 weeks or so). Any idea if this is something that could cause problems with the emission test?