id get a second opinion, but as a mechanic i know that coincidences like this happen a lot and they seem fishy. so he may not be trying to pull anything. can you tell that there is a new mass airflow installed? if you have a multi-meter or even a stethescope, you can check that injector yourself. and i would check the plugs, even if they were just changed. many people use bosch platinums for replacement, and that is the worst friggn plug out there. i dont use them anymore because of the come backs from them....
Just as a follow up. I had the injector replaced yesterday. This morning the check engine light came back on. So, basically I just spent $750 on parts and labor that didnt' fix the problem and I get to start at ground zero with another mechanic. It's not that I feel they are intentially trying to rip me off, but I told them when I went in there I didn't feel like it was a sensor or an injector and that it was part of a bigger problem (likely an intake or vaccum leak). They looked and couldn't find anything but now I am almost certain this would be the case.
Just as a follow up to those of you who are following along. I took it to a difference mechanic who hooked it up to a diagnostic machine and now it's kicking off a P0430 Catalyst System Efficiency Below Threshold (Bank 2). They said they couldn't find anything wrong with it besides that code. It stills runs awful when it's cold outside but fine when it's warm. Does that code shed some extra light on the problem I am having? I found a thread that was saying Nissan could reset the ECM to allow get rid of that code but I also found threads saying the catalytic converter or an oxygen sensor is bad. I can't seem to get this taken care of no matter what I do.
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.
Posting on this thread as a last ditch effort before I give up and buy a new car. I replaced the MAF, fuel injector, spark plugs, catalytic converter, ECM foam, and crankshaft position sensor (the last 3 were replaced by the dealer and no charge because they were under warranty). The car runs much better now. HOWEVER, it stills runs awful when it is cold. A couple people mentioned an exhaust leak could be the problem. Are there any tools I could use myself to diagnose this? Is it fixable by me or would I have to take it back to the dealer? Any help would be appreciated.
wow. i feel for you. Are you still getting SES codes popping up? There are a couple of things that may cause some of those codes... fuel pressure problems, dirty fuel filter, vacuum leak, oxygen sensors. .. I'm not sure what else. The fact that you've seen some improvement from the MAF sensor seems to say something.
No check engine light or error codes but the car feels the same jerking and rpms reving up and down when it's cold. I am starting to wonder if it isn't a bigger problem that was causing all of those parts to go bad. Could a vacuum or exhaust leak cause a fuel injector, catalytic converter, etc to go bad? Or am I just unlucky that all of this is happening at the same time. It seems a bit fishy that ALL of these fuel/air system parts are going bad at the same time.
for me to give you any further help, id have to have the car here so that i could do a test drive with my scanner hooked up and record some data. its ashamed that the nissan dealer can not help you find the problem in their product. or have you taken it to them yet?? id go to a technician that is noted for import drivability specialist or the dealership.
Check intake for leaks. Turn on the engine, open the hood, rock the plastic intake part HARD, and see if the engine surges or stumbles. Also, try to pull on the throttle cable if you can see one. Then spray some WD40, starting fluid, or carb cleaner on the entire intake plumbing, and watch for any change in engine operation.
Kick your mechie's ass - MAF sensors rarely fail, and when they do, they do so gradually, or die altogether. At least make him give you the old part back, I bet it's still good. Any improvement was because they shifted the intake boot around while changing it. Intermittent failure means an intake crack, period. Which is why it throws codes - too much air gets in, hence it misfires. I hate OBDII, it was made so that mechies would make people buy tons of new parts for no reason.
If you haven't done any maintenance lately, change your plug wires, distributor rotor&cap (if you've got one), fuel and air fitlers, and PCV valve. You can do it yourself, or have some shop do it for you real cheap. Just don't go to the same shop that made you change your MAF sensor. What a ripoff.
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93 Sentra XE 5spd, running well... 82 924 Turbo under construction... 82 Suzuki GS650G, under construction... 76 Firebird Formula 5.7, waiting for the next summer.
Last edited by Petrovich : Jan 12th, 2006 at 12:55 PM.
No check engine light or error codes but the car feels the same jerking and rpms reving up and down when it's cold. I am starting to wonder if it isn't a bigger problem that was causing all of those parts to go bad. Could a vacuum or exhaust leak cause a fuel injector, catalytic converter, etc to go bad? Or am I just unlucky that all of this is happening at the same time. It seems a bit fishy that ALL of these fuel/air system parts are going bad at the same time.
I don't know if this will help you but on my 1992 Sentra it had a horrible bucking problem at low speeds and I was convinced it was an engine mount or fuel delivery issue......
I traced it to a broken wire inside on the Mass Air Meter harness so when I decelerated the wire which was broken (the wire sheath was intact) would make contact and the Mass Air would read and bump the fuel and when that happended the engine bucked and disconnected the wire and the Mass Air would cut off....
I cant believe I ever found it....... Well at least I have new engine mounts...
I have a somewhat related problem to the engine issues explained here. In my case, the car starts jerking when i slow down or when i am (stopped) at a stop light with the car in "drive". This usually is worst when i turn on the A/C as the engine seems to want to shut down (and it has happened a couple of times at stop signs) when i am not accelerating.
When the car is rolling, it doesnt jerk but i do notice a "misfire".
Also when the engine is "cold" it starts fine but after its been warmed up if i need to start the engine i have to accelerate for it to start.
These problems "appeared" in a matter of...say, 5 days.
I first took it to a mechanic and they couldnt diagnose the problem. Then I took it to the dealer (hoping for some expertise) and their diagnostic was that the cylinder head was "cracked" so they told me that the whole cylinder head needs to be replaced along with sensors, gaskets, oil and coolant, etc. In the end the "estimated" costs they projected ascend up to 2500 US$. This is a HUGE amount of money for me and its almost 50% of the cost of the car in todays market value.
Has anyone had this problem and maybe could help me out? I'm not an expert by any stretch of the imagination but I'm hoping that there is an alternative solution to this problem. If anyone knows and/or needs any further information please dont hesitate to contact me.
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