92 240sx Running rich, making me poor!

[240FeVeR]

I'm pretty familiar around cars but before I go about replacing anything that will put a dent in my wallet I always want to get a second opinion!

My 92 coupe is running pretty rich, you can smell the overly rich mixture at a warmed up idle and fuel economy has become unacceptable. The engine runs very smooth and idles very well.

The car is VERY well maintained. Oil is fresh. Spark plugs, distributor cap/rotor, air filter are all brand new.

I've checked the oxygen sensor according to the FSM and it checks out to be in working order (changes from rich to lean more than 5 times within 10 seconds running at 2000 RPM in neutral). I have a Techtom btw. I tested the air flow sensor according to the FSM and it's working perfectly.

My only concern is the throttle position sensor, and I don't know how much this would affect fuel mixture. The FSM says the TPS should read 0.50V +- 0.2v closed throttle and 4.00V WOT. I was at 0.44V closed and then adjusted to 0.50, but couldn't get my WOT voltage to raise, it reads at 3.62 at WOT. Do you think this calls for a new TPS?

Thanks!

[srblacks131]

check the FPR and the lower injector O-rings. Take the vaccum line off the regulator and if gas comes out that means the diaphragm is ruptured and needs to be replaced. The O-rings you cant really check but its not very hard a job to do and could be done to make sure that is not the problem

[driftingmy240sx]

tps sounds like it is fine. the maf voltages can be misleading. you need to monitor grams/per second with a consult to really rule out the mass air flow also fuel trim will be incorrect if the maf is bad.

[nissan_4_life]

could bad fuel injectors be the problem

[freakyjason]

If youre still having problems with it, i'd check the idle air control valve (iacv). sounds like what was wrong with my car.

[boriquaS13]

Your TPS is O.K. You will need to check all the other components that can cause this condition fuel pressure, leaky injecter,fuel pressure regulator, coolant temp sensor also the connector for the coolant temp sensor.