I have a 96 Sentra which has been sitting for two years. it has 240,000 miles on it. It runs smooth but will not pass California Smog. What parts can I check or replace to improve the chances of passing smog. This car has been well maintained and only freeway miles. Thanks

if cali hooks up to check electronics is only way

It won't pass smog in California because the 1st thing a smog tech does it check for fault codes on the vehicle's computer with a scanner.

May need to have the PCM reprogrammed by a reputable shop.

No way to "cheat". Master emissions mechanic is the only solution.

150 miles at least also check ur air filter change nice clean one

Does it also run quite rough (loads of vibration) and then smooth out when it gets warmer? The air to fuel ratio may be off for the carburator. Can be adjusted using the a small screw jus underneath the throttle body. It can easily be reached without having to remove any parts. there are other reasons as well, but this solution is the only one you can do without replacing parts or tearing apart the engine. Also, depending on the state your in (California for example) it will not pass more modern emissions standards.

There are two type of emission classes.

Federal and California emissions.

Look under the hood for the emission class sticker.
Smog check station's machine in CA are programmed to handle both types.

You do not need to change anything before the inspection.

==== Side notes: You should check the service record for the last Catalytic converter,O2 sensors and EGR valve change.
Service interval for
Catalytic ~180,000 miles O2 ~150,000 miles EGR ~160,000 miles


If you can locate the last smog test (even from out of state) Check for the
CO NOx

I had same problem so I changed all the vacum hoses by intake manifold they were like 9 and they adjusted the timeing and my idle was almost at 1.8 so they drooped it to .700 rpms and it passed with flying colors and added octane buster and a full tank supreme gas...

Yes you can. 2000 Cadillac should have a northstar already in it.

Try running a tank of Supreme gas & a can of SEAFOAM in the gas tank. It might clear up your problem????? Go chance of it.