My car has developed a "missing" or "stuttering" at ~30 - 40 mph at light throttle. It FEELS like the tranny is "hunting", you know like when you give the car moderate throttle and the RPMS kick up... well it FEELS like it is unable to decide if it wants to kick up or stay where it is at. This is VERY noticable. The problem will go away if you give it more gas, or if you let off the gas. The car is an 89 GXE Automatic with 159k miles on the original tranny / motor / fuel injectors, it has a tranny cooler on it and the fluid is fresh and has never (that I've seen) burnt the tranny fluid. I KNOW that one of my fuel injectors isn't quite up to stuff, but it hasn't caused a problem other than when I hot start the car. (The car will miss for about 2 - 3 seconds and then continue on and not cause any more problems) I'm not sure if this issue could be the motor or not... I've described what it "feels" like and hopefully you guys can get an idea from there.

Any ideas / suggestions are appreciated,

Thank you,

 

The dealer can do a power balance test, which will tell you if injectors are clogged or leaking or fried. You can test the DC resistance on them to see if they are all close in value. I just recently did a current load test to see if they were drawing the same amount of current. Next thing that I have to do is a pressure leak-down test to see if any of them are leaking (which is what I'm suspecting) . But the easiest thing to do is to go to the dealer for diagnostics for like ~$80. then if you can do the work yourself. good luck.

 

Did I hear "Power Balance Test"? I asked around the General forum a few months before what the heck this was, and only 1 person had any suggestions. I'm asking because the local auto association (like AAA) said they did this instead of a traditional compression test when they inspect your car.
So, please tell me all you can about this test and what it can tell you about the engine. Is it worth the extra time and expense to get it also compression or leakdown tested? Thanks in advance.

 

Thanks Eric. I guess I need to look into that... So you think it is probably the motor?

Thanks,

 

The only problem is that they wont sell it and it goes for around $1400. It's unfortunate that our third gen's aren't apart of the standardized diagnostic tools they have for cars today (I believe '96 and up). Yeah, you can get a full diagnostics work-up for around $80. The diagnostic tool is able to breafly disable injectors or ignition coils and then it calculates EACH cylinders power contribution in the form of rpm's. So you know whats going on. The Consult will do many other things (except fix you engine for you ).
It has a data monitor mode so that problems can be diagnosed while driving, ex: timming etc.


Bman, Only the dealer can perform this test because there the only ones that have it. Although I dont think the consult is able to do a compression test. That would probably need to be done the old fasioned way.

Brian, have you changed the fuel filter yet>?

 

It might just be your throttle posision sensor (TPS)
The problem your describeing sounds alot
like the one that I had on my 90

if the missing is only happing at a perticular
part on the throttle meaning if at light throttle
and heavy throttle its ok but stumbles or
completely cuts out at mid throttle
that could very well be it

 

Thanks, I just checked that last night and it appears that the TPS is working OK. I just checked the resistence last night, however I checked it while the car was cold and I usually only happens when the car is warmed up. I'm going to get a new cap and rotor (needs it anyway) and see what happens tonight. If those don't fix it I'm going to look into the TPS some more. One thing that I've determined is that the problem is NOT the tranny!!! :-)

 

Ok guys well... I figured out what the problem was. Basically it turns out that just because your ignition system was in good shape 6 months ago doesn't mean that (15k miles later) it still is. :-) I replaced the rotor button (Nissan), distributor cap (Nissan), Plug Wires (NAPA), and spark plugs (NGK). Car runs normal again!!! I thought for sure that it was an injector, but when listening to them they all seemed to be consistant with each other so I looked at the ignition... Funny, my RX-7 gets new ($4 a piece) plugs every 2000 miles and I forget and let the Maxima go probably 90k miles on a set of plugs... SHAME ON ME!

BTW- I think have a solution for my door locks mysteriously unlocking as well. I'm going to test it out and let you guys know if it works.