pump or injector?

 

One would probably show low or inconsistent fuel pressure. The other might show high ohm load or an odd value as compared to the other injectors. I suppose if an injector is leaking or is stuck open, the plug would be dirty. Why do you ask?

 

Because I have a problem.

I've had the injectors cleaned, done the spark plugs/wires, fuel filter, cleaned the throttle body and air filter.

When I had the fuel injectors cleaned, they did the diagnostics and came up with a bad O2 sensor (code #33 I think it was).

So maybe it is true that the O2 sensor needs to be replaced...what are the symptons in "driveability" that indicate a bad O2 sensor? btw, what is purpose of the O2 sensor?
Also, I was thinking that the thermostat may be bad.

Is there a difference in "driveability" with a bad fuel injector and "driveability" with a bad fuel pump?

I'd really like to avoid the fuel injector repair - $$$.

Thanks Jeff.

 

If they cleaned your injectors, they should have noticed if one was shot. When I had mine done, the mechanic even showed me what was wrong. (He's a family friend, I doubt most mechanics will actually show you, but they should at least notice it.) The purpose of the O2 sensor is to measure how much oxygen is in your exhaust to see if your engine is running efficiently. There should be one before and after the catalytic converter, but I'm not sure where they are on all years other than 90. If your thermostat is bad, you will experience overheating (if it's stuck closed), or your car will never warm up (if it's stuck open). If you have a bad fuel pump, most likely, you won't be able to start the car at all, and if you can, it will probably sputter and hesitate alot. Most of these repairs are minor on the scale of things, but don't expect to get out of this without spending a good 100-150 bucks, assuming you use salvage parts, which really isn't the best idea, as I've found out. This isn't gospel, so you may want to wait for Jeff or Matt to give you their 2 cents. They're the real authorities when it comes to tech questions.

 

Thanks for the input, crusher!

The Nissan techs didn't show me anything...but said that the O2 sensor was probably shot.

As for the O2 sensor, I am only aware of one before the cat. So what is so bad about having a faulty O2 sensor? How does it affect the way the car drives?

Now for the thermostat, it seems that it's stuck open. The gauge will often read "C," but will sometimes read normally.

It could be the fuel pump. The car starts without a problem, but it does sputter and hesitate alot.

Again, thanks for the help!

 

O2 After the cat? on 3rd gens?

I didnt really notice, but last time I was under my car (granted ive only had mine a month) i didnt notice an O2 after the cat. granted i wasnt looking either..heh...

I was under the impression however that only OBDII (96 and up) vehicles used an O2 after the cat. Like i said though, im not going to bet any money on it...just thought I'd mention my thoughts....Its 1am and im not going out to look under my car :-D

 

3-gens have one 02 sensor. It's job is to monitor the A/F ratio and send a signal back to the ecu to either richen or lean out the mix. There is an ECU check to see if the 02 is working okay

A bad 02 sensor will usually result in poor gas mileage. Dunno about drivability. If you want to check the fuel pump, hook up a fuel pressure guage and check it for proper pressure.

If you still have the stock one, it could be going out. But by your description, it could be other things too.

 

Dammit, what good are you?!? jk

Gas mileage has been better, but it's not terrible. I was getting ~20 mpg with mixed driving the last time I checked.

I'll try the fuel pump. That was also suggested by a friend. It's not making difference with a full or 1/4 tank, so...

Thanks.