350350

Other possibly relevant tidbits-

The car is smooth and quiet, and you'd never guess it's running long tube headers. No obvious exhaust leaks. If it has any, they are so minute that I cannot hear them. It has a cat-back dynomax muffler and dual 3" outlets.

Since we knew little to nothing about the car, our fist major outing in was, of course, the drag strip! It ran a best of 8.95 in the 1/8th mile on a cool 70 degree evening. Not at all what it should run. Its first pass, it backfired halfway down the track (out the exhaust), died, and then restarted after coasting to a stop and ran fine the rest of the night. Several more uneventful passes got us consistent 8.9-9.0 times in the 1/8th.

It runs perfectly fine. No hesitation, noise, knocking, or any indication of a rich running mixture. Honestly it's the smoothest running car I've ever owned.

When we bought the car, it had no muffler at all. It sounded like Satan gargling on the blood of the innocent. It was setting these codes then, without a muffler. Since then, we put the dynomax on it (another craigslist cheap find) without resetting codes. Dragstrip runs were with the dynomax on.

Injuneer

Given the history (or lack thereof) probably a good idea to go through the exhaust, looking at the quality of the O2 wiring (extensions). Corrosion can cause major problems when dealing with such low voltage. Then replace the two pre-cat sensors. Any particular reason you want to delete the two after-cat sensors, while apparently keeping the cats? If the cats aren't working, why keep the cats?

You are correct, you only need the pre-cats. Rather than using sims (which seems to be hit or miss, since the Feds shut down Casper's sim operation) in place of the after-cats, you could have them programmed out of the PCM with a mail order tune.

350350

My main thought was that I need it to pass emissions in about a month. If simulators were a cheap/quick fix for the cats, I'd just do that and then make changes to the exhaust when time allows.

I'll inspect everything, and replace all the O2 sensors, (found the Bosch ones for $22 each on amazon) and run the cat cleaner through it. If that doesn't get me to a place where I can pass emissions, I'll go ahead and take the cats off and have the rear sensors tuned out. There's a reputable shop here that will do a dyno tune plus program out the rear sensors for $350. Since the car has some bolt-ons, I figure the tune would be nice.

How does that $350 compare to the mail order tune you mentioned? Do you have a recommendation for a mail order place?

Injuneer

Strongly recommend you use only AC Delco or Delphi O2 sensors. Many people using Bosch have reported problems.