GREGGPENN

Thanks for confirming my suspicion and I understand the responses. If the exhaust requires monitoring to insure proper operation, then 8 sensors seems even better!

I always thought it was stupid to have only 1 O2 sensor on a dual system, now it's clear why.

As for the air pump, it only puts air into the manifold during open loop so I don't see that as an issue. Without the presence of fault codes and with a relatively new O2 sensor, plugs, wires, cap, rotor, and coil, I gotta think that fuel delivery is my primary area for improvement. (And, I did not overlook vacuum leaks).

With new ignition parts, it actually runs better than it did in 1999 when it had 14k miles and was 10 yrs old. So, I'm not as concerned any more. But, it shows that I should not have been misled by the new appearance. I also think the wire routing is iffy -- since mine appeared worn thru and shorting as it made the turn around the valve cover. I also bet that a smooth running motor lasts longer by reducing wear thru lack of vibration!

Most importantly, I'm PO'd that I paid over $100 to Superior Chevy for a diagnosis. They found nothing wrong. A shorting plug wire should have been easy for them to spot. (The wire had a visible breach in the insulation). Any bets they'd refund my money?

I will replace the injectors this winter. In the mean time, I need to figure out what brand to use -- since reports here seem to heed caution. Til then I need to finish my interior redo.

Gregg

Mike_88Z51

I'd take a picture of the wire and go down to the stealership with the invoice and ask for a refund. If they refuse and you paid with a credit card (always), call the CC company and dispute the charge. Then immediatly send the stealership a letter with the reason for your dispute and a copy of the wire pic. Make sure to request a response in writing within 10 business days. This is s a simple letter that describes why you feel that you were charged for a professional diagnosis that wasn't done professionally. Don't worry about being legally appropriate. Just state the facts for your CC dispute and ask for an answer and full explanation from them on why the problem was missed within 10 business days. It's not the letter itself, but the fact that you wrote a letter that is important here. Also, very important, have the letter delivered with delivery confirmation required. This costs only a buck or two. The post office puts a label on the envelope that requires the delivery date be recorded by the delivery person. It doesn't really do you any legal good and the stealerships know it, but it signals to the stealership that you are not the normal patsy and are serious, so they usually fold and let the CC dispute stand. It costs them more to have their lawyer look at your letter and respond, than they charged you. Plenty of others who are easier for them to rip off.