O2 sensor

brusch

#204 of 204 1990 Nissan Stanza GXE...? O2 Sensor ? Gas Mileage by brusch Jul 02, 2001 (06:09 pm)
I'm getting only 14mpg on this 2.4cyl car when it is supposed to get near 24mpg/city. The engine light has never came on.it runs great. I have had it checked by numerous mechanics including Nissan but none can find a problem.
Is it possible to have a bad O2 sensor without the engine light coming on? Could it be something else that is causing such poor gas mileage that might have been overlooked?
Bill

0patience

I would confirm the light actually works, before condemning the O2 sensor.
Everyone wants to replace the O2 sensor, never understood why.

First, lets look at the basics.
How long have you owned the car?
Has it always been like this?
What, exactly has been checked? (well, I could start listing things , they may have already been checked and that would be wasting your time and more importantly, mine)

Has the exhaust been checked and has the fuel filter been replaced?

brusch

I've had the car 3 months,bought it as 2nd car. Had 93,000 miles now has 94,000. I had it tuned...new plugs,wires,cap,fuel and air filter.new exhaust,battery,fuel system cleaned,tranny and coolant system flushed and filled. Can't think of much else that can be done other than pull the engine..Ha! It's sure not worth that. If it ran poorly maybe it could be easily diagnosed,but it runs great just terrible gas mileage.
Bill

0patience

What was the fuel pressure?
If they didn't check it, they should have, especially if they "cleaned" the fuel system.
If an injector is bleeding by or leaking, performance may not be affected, depending on the amount of leakage, but fuel economy may suffer.
How many miles are on this thing?
Has the compression been checked?

Mr_Shiftright

I'd like to see how this car smogs on an analyzer. This is a drastic loss of fuel economy. Only a leak or a fairly conspicuous problem could cause this, seems to me. Compression test for sure. You got air in the tires?

lngtonge18

I owned a 91 Stanza and know from experience that the 2.4 is not very fuel efficient. Granted your mileage is very low. However, you only went 1k in 3 months? Sounds to me like you make a bunch of very short trips. That could very well lower your mileage drastically, especially if the tires are low in pressure as well. This engine was only rated at 22 in the city with the manual and 21 with the auto. I currently have a 97.5 Altima with an automatic that has the same exact engine but with a twin cam 16 valve head and have gotten as low as 17 mpg in all city driving when the tires were low. The other possibility is that your fuel injectors are leaking. This was a known problem on some 90-91 Stanzas.

juanfe_trade

I just bought a Toyota Camry 1991 V6 AT, it has 155 k and I am having a bad mileage (aprox 16MPG). A week ago the engine checking warning light came up and in the body shop they told me the O2 sensor is not working properly (getting lazy). My question?
1. What other stuff should I check in the car before I decide to buy a new O2 sensor?
2. Does anybody know where can I buy a O2 sensor for a very good price (for me of course)
Thanks