My check engine light is on,I could not pass my smog test,I was told it could be the cat & fuel injector module board?

A tune is just replacing the spark plugs every 100,000 miles and the air filter every 30,000, clean oil is also a help in passing smog, the new converter is what will most likely do the trick.

wow ,no posted smog report, (the failed gases) now that makes this 10s harder, and for sure more expensive.....
many post,. why not just add to one post
click comments and add.
or edit one. post.
all engines that fail smog run fine. (so says all owners)
(fine means zero,) in the real world.
what's worse is owning a 1995 in USA, and must get sniff tested.
(cant fool that method) no report by you, (paper)

ignore all statements by all smog testers,
only one statement (it fails!)
all others are lies, guessing and BS.
after all if they were fully trained and skilled they'd have a real job.
a fact. (or they get huge retirements from the state?)
The car needs to be check by a pro.
it needs to be scanned, with a custom scan tool that is not sold in any auto store until 1996 happened.

but if that NOT IN THE CARDS./ no money for a real ASE tech?
then yes, do a tuneup..

1: spark plugs. and new wires, cap and rotor.
2: filters. and fresh engine oil, (the oil can be full of gasoline is why)
3: the cat may be ok, is spending a fortune on that good?
on a wild guess,? like your smog guy quipped?
that be your call. no? (shot gun method or testing) your call.

in a shop they would get the engine running perfectly.
in closed loop hot and light cruise.
A NEW front 02 sensor for sure.
then they test the cat last, the CAT is always last.
i think this car has 3 way cat too, so is really 3 cats in one.
all 3 must work. or you fail... (for sure)


what if only NOX gas failed.????
if yes, we fix EGR first. then CAT last. (they work as a team)
what gases failed matters
and was not stated by you.
in a real shop they can sniff front of cat and rear
and tell you ,
bad engine, or bad cat. in minutes.
or both, sure.

bad engine means
1:engine is bad.
2: EFI controls failing, (fuel or spark)
3: misfires. (even some humans cant hear, omg)
4: and many more. but no smog sheet posted, no savvy.

a pro shop knows the pre cat gas levels that are normal.
if they are, then the cat is bad.
end story.

Considering the age of your car I suggest first having the injectors checked and the fuel pressure regulator.

There might be no trouble there but if they aren't in good order it will be difficult to get a pass and any new parts such as oxygen sensor and/or cat will have a much shortened life and the engine is likely to give low mileage and lower performance.

You should also have the engine thermostat checked and if necessary replaced to ensure a complete warm-up. The temperature sensors and air metering system could also be rather tired and sending misleading information to the engine ECU.

A new cat and an oxygen sensor would probably produce a test pass but would be a false economy without ensuring the basics are ok first.

Is your check engine light on ? Fuel comp. is fuel system monitor test complete , along with HO2 , misfire , cat, etc... Nothing wrong ! OBD Readiness Monitors Explained OBD Auto Doctor Scantool Garage

Check for loose or faulty gas cap.

Robert, High emissions usually mean the EGR valve and several hoses and other smog components are clogged up. There is no easy fix, you have to get the shop to check through the smog system on your car if you cannot do it yourself. Type of driving, short runs, high miles, burning oil etc all contribute to the engine giving a dirty reading. It may not be enough to light the lamp but it'll be dirty enough. Of cause, it may be the lamp is bust as well? Does it test light when you start up?

P0420 - Catalyst System Efficiency Below Threshold (worn out cat.)
Possible causes- Three way catalyst converter Bank 1
- Exhaust tube
- Intake air leaks
- Fuel injectors may be faulty
- Fuel injector leaks
- Spark plugs may be faulty
- Improper ignition timing
- Engine Control Module (ECM)

What fault code is being set?

IF DECELERATION FUEL REDUCTION SYSTEM IS NOT OPERATING, FUEL ECONOMY WILL BE REDUCED WHILE HC AND CO EMISSIONS ARE INCREASD.SEE ON MANY ENGINES WITH DECELERATION FUEL REDUCTION SYSTEMS THE PCM STOPS GROUNDING THE INJECTORS IN A SPECIFIC RPM, DURING DECELERATION.

Hello.

Normally, the P-0420 indicates a sensor issue; a cat replacement would be needed if you had the P-0420 coupled WITH a
P-0430 code.

What I would do, if I were you, would take the car to a shop that can perform an "induction cleaning", and have that service done. Then, replace the spark plugs, if the car is around 90,000 miles. You may alsop need a front air-fuel sensor (the one on the manifold) replacement.

I would not change the cat until I did the above services. It does not sound like a bad cat just yet.