96 9c1 lt1 02 sensor code questions.

I have a 96 caprice 9c1 LT1 with 164K. Its showing 4 codes, I didn't write the code #s down.
1 is the secondary air injection (air pump), got one off e-bay, still need the exhast valves before I install it.
Another is random multiple cylinder misfires, which I think is probably the opti-spark, because it started shortly after I replaced my water pump.
The other 2 are for the downstream 02 sensors, 1 has no activity and the other is a heater circuit malfunction.

My car noticably misses especially after warming up. It seems to be worst around 40-45 MPH going up a slight hill. If I floor it it runs fine at higher RPMs. Does that sound like an opti-spark going bad?? Could the O2 sensor problems be due to raw fuel through the exhaust from it missing?? Any other possibilities?

Thank you
Dustin

There is a TSB on the A.I.R. system meaning a Chevy dealer will lawfully defeat the system for you at a pretty reasonable price, not that they have to be the ones, just making a point about the fact it is legal.

The aftercat O2s are not used for anything but a tattletale on the cats. If they go bad I suggest getting new sensors putting them BEFORE the cats and putting the old but functional ones from in front of the cats behind. That way you use the new O2s to get better fuel economy.

The miss could be just a worn cap and rotor, they are most often grossly neglected till some stupid person curses the opti as a bad design when neglect is the real culprit, ALL cap and rotor setup are wear items just like sparkplugs.

On the uphill miss I might check operation of the EGR, another TSB item that GM voluntarily extended the warranty on.

when the manifold check valves fail exhaust gases and water get into air pump then from air pump to maf. this is where codes and misses are caused. step 1 replace pump and check valves use oem check valves as aftermart valves are not the correct diameter for hose. the dealer can disconnect all this but my in area the cost was excessive so i repaired as designed. maf does get dirty so clean or replace my be necessary.

Thanks for the info. My only complaint about the opti design is that it is positioned where you have to pull the water pump in order to remove it, but I also realize that you can only have so much accesible and still keep it compact.

As I stated before I recently replaced the water pump. From what I have read when the water pump goes it drips coolant directly on the opti from the weep hole, causing problems with the opti.

It has been missing for probably around a year. I usually have another car I can drive, so I only drive it occasionally. Lately everything has been breaking on me. In 1 week we went from 3 drivable cars to 1 (my caprice). We're back to 2 and tomorrow I should be able to make it 3 again.

Considering how long it has had the miss, could the unburned fuel cause the cats to go bad? I replaced one of them a couple of years ago along with both o2s on that side (passenger side if I'm remembering correctly).


Dustin

Thanks for the advice. A van turned left in front of me on 1-2. Happy New Year. My car is probably totaled 3 times over. It was still running after the accident, though it would have overheated quickly with the radiator destroyed.
Dustin