[knarf]

Catalyst
Evap
O2
O2 heater
EGR

'96 GNC Sonoma 4WD, owned three years and inspected by the same mechanic with no problems ever.

Need Emissions inspection in Pa. and the machine won't even begin because here are 5 incomplete readiness status results.

My mechanic is baffled.

Truck runs good, no code violations, no problems etc.

I haven't disconnected the battery or asnything.

I have to the end of the mjonth to get inspected.

Are there any automotive magicians here that can help ?

Thanks

[Bullish]

Fuel leak somewhere? Faulty gas cap?

[Army Air Corps]

Ping.

[TexasTransplant]

Check your Air Cleaner? Is it running rich?

[SkyDancer]

A friends Isuzu Trooper will get a check engine light if the gas cap is not securely tightened. It’s part of the whole EGR, etc system.

[who_would_fardels_bear]

Is this vehicle moving to a new state? I moved from Colorado to California and failed my first inspection because, without notifying me, the technicians at the smog checker in Colorado had turned back my timing so my car would pass.

Evidently this was counted as cheating in Cali, so I had to have my engine retuned in order for it to pass in Cali.

If PA is a new place for this vehicle then you may want to check what's different between where you are and PA.

[RckyRaCoCo]

South Main Auto(Eric), New Level Auto(Keith)...lots of great mechs and techs on YouTube

[Nateman]

Played that game before. I kept on replacing possible parts with no luck. The Engine cracked before I could hunt it down making my efforts pointless. Next time I'm going to register my car in a place free of smog inspection requirements.

[mabarker1]

Do You fill the Fuel Tank ALL the wat to the top of the Filler neck so that You can see the Gas up where the Cap is ? Even 1 or 2 times ?

[mountainlion]

Different story but 2007 GMC 1500: ABS light on, check engine light on, service 4x4, no low gear on transmission, no overdrive, starts off in 3rd gear unless manual downshift, no downshift for hills. There were no engine codes. $125 later the solution was found for $1.75. Fuse # 20 fixed it.

Check your fuses.

[posterchild]

vacuum hose missing?

[Gen.Blather]

Most likely culprit is a weak battery. Follow the advice in this article.

https://repairpal.com/drive-cycle-issues

[ebshumidors]

It sounds like these systems aren’t reporting to the DMV computer. Try taking it to another location.

[ebshumidors]

A gas cap will give you a light and an eye code.

[rockrr]

Clogged catalytic converter? (Yeah, I know it’s a stretch but I had one fail for that reason).

Good luck!

[right way right]

Get a new mechanic.
I would check EGR passage.
Is it a 3.1 litre? They plug easily.

[refreshed]

Maybe it’s running rich. It may be timing, plugs and wires need changed, rotor, cap. I’d definitely check those first if it was

[Artemis Webb]

Easy answer.
Gremlins.

[fruser1]

I’d disconnect the battery first to reset codes. See what comes back.

Secret Alternative Option - Many states allow cars that are 19 years old or older to get historic tags. No emission test required on those, however, legally, mileage is limited.

[outofsalt]

Not a mechanic nor did I stay at a holiday inn express.
I believe if un-combusted fuel is making it to the exhaust system it can gum up the catalytic converter. Are your plugs fouled? Timing off? Mixing too rich?

[Vermont Lt]

Even though the battery was not disconnected, it sounds like something electrical is hitting your sensors.

You might want to try it on a fresh battery. Just to clear that from the list.