Coworkers 97 Nissan PU

[DrDusty86]

I was told by a lady I work that her 97 Nissan pickup recently had a massive drop in fuel milage. It is the 2.4L with an auto. She was getting 21mpg, now its getting 13-14mpg she says and has NO power. I was told that is has new air filter, plugs, wires, fuel filter. Tires set at 35PSI, but has a Check engine light on that she claims flashes sometimes. Truck has 156k miles on it.
I told her to run it by Autozone to get the check engine codes then let me know what they are.
Nissan guys, Anything prone to failure on these models?
Help,
Dusty

 

[chainblu]

Well, Autozone will probably be able to tell her more than anybody here. But, my first SWAG would be Oxygen Sensor due to the age of the vehicle...

 

[daves87rs]

Maybe the Cat is clogged?

 

[UncleS2]

Not specifically for Nissan pickups, but for just about anything doing that, has anyone checked for a bad vacuum leak?

 

[hooligan24]

check for stuck brake caliper.

 

[eljefino]

I like the stuck brakes but want to throw in a stuck open fuel injector or messed up (leaking into its vacuum line) fuel pressure regulator as well.

 

[artificialist]

Those engines had problems with wiring to the IAT (intake air temp) sensor.

Also, see if the Engine Coolant Temp Sensor works properly. If not, the engine will stay in open loop mode, burning extra fuel, and the check engine light will probably not come on if the sensor is giving a realistic temperature reading.

 

[hypervish]

If the check engine light is blinking, it could mean the engine is misfiring.

 

[Kuato]

If all the problems occurred suddenly, after the work was done, then she should have that work looked at again.

 

[FowVay]

My '97 gets around 24 or 25MPG with a manual transmission. It did have the broken wire to the inlet air temp sensor which was intermittent. I'd reset the light and it would be fine for a few weeks. Then it would illuminate again. The wire was broken to the sensor. It's a $30 fix.

There's nothing tricky about the engine so a huge drop in mileage should be caused by something obvious. I can't imagine 13 MPG even towing a house with that little thing.

Maybe someone is siphoning her fuel at night.

 

[The_Eric]

Originally Posted By: eljefino
I like the stuck brakes but want to throw in a stuck open fuel injector or messed up (leaking into its vacuum line) fuel pressure regulator as well.


You beat me to it...

I'll add that if it is an injector and you do replace it, be careful. Once you remove it, fuel can pour down the intake and flood that cylinder and possibly cause hydrolocking and/or a bent connecting rod. This is a known issue with the Nissan injector set up.

 

[CBR.worm]

MAF? Just did one on our '97 Nissan PU with similar symptoms - but ours smoked and smelled way rich. It was available w/o the venturi.