I'm no emissions expert. If there is a forum member that is they would be best to get an answer from. Which test did it fail, idle or 2500rpm? When analysing emissions you need to know the relationship between all the gases, HC, CO, NOx. High HC is unburned fuel. Is your idle smooth? Could be O2 sensor or catalytic converter, or misfire, even dirty air filter. This may be one you need a tech for.

 

check your pvc valve. high HC is caused by a clogged pvc valve amung other things.
when you remove it, shake it and it should rattle, as there is a small ball inside. If it doesnt rattle, then you know that's bad. A new replacement is real cheap.

 

The HC looked highest when the car was at higher speeds and lower at higher speeds..91 Camry 4cyl do not have a PCV valve

 

The funny part about this is when it first got the emission test the NOx failed, after replacing the plugs, wires, dist, rotor and EGR valve the NOx was fine and the HC is high. I used Premium gas before the first test and regular before the second test..any coincidence there?

 

Hey Pedro, one of the items on the website you gave is adjusting the ignition timing...How is that done? and where is the adjustment screw?

 

What is the purpose of the EGR solenoid?

 

Timing - you'll need a timing light. Not sure on the 91 but you may need to jump two connections on the service connector, check the hood for timing and adjustment procedure. There will be two bolts on the distributor to loosen and then turn the dist. until timing marks align. Better get a Haynes manual, cheap reference, $18. If you need to jump wires timing s/b 10 degrees BTDC.

The EGR solenoid turns theEGR off/on depending on idle/cruise/wot.EGR is closed on idle so car won't stall - remember how yours would not idle.