Dreaded Check Engine light fiasco

[TXHokie]

I have a 98 Accord and have had the check engine light on for several weeks. Since it wouldn't pass inspection like that, I figure I'd try to get it fixed. Took the car to Autozone and had the code checked and it indicated that I had a loose fuel cap? I bought a new cap and ran half a tank and the code wouldn't clear so now I had to take it to the shop. They kept the car over the weekend and did some kind of smoke test and said they had to replace some vacuum hose that was old and loose. That was $150 plus inspection fee but the CEL cleared. A week later the dang CEL light came on again. Back to the shop and after more diagnostic, they said now the code shows I got a bad catalytic converter and need to replace at $380! Heck I was about to have to get my timing belt replaced so I'd figure I'll defer it and get my timing belt done first. Had my mechanic replace the timing belts, water pumps, and I figure what the hell replace the spark plugs as well for maintenance. Lo and behold I drive it for two days and the CEL went away and has not returned for several weeks. In the meantime I've been looking around to replace the cat converter just in case but looks like I don't need to now. So what the heck is up with the computer giving bad codes like that? Or is the shop just suck at fixing my car or scamming me.

 

[NutBucket]

The computer isn't perfect. It doesn't have the same troubleshooting capability of a good mechanic

That said, I believe the converter has a 10 year warranty anyway. I believe that's a federal mandate, but someone may correct me and say its a California-only thing; but I kinda doubt it.

 

[Vic]

Cats have an 8 year/80,000 mile warranty mandated by the EPA for all vehicles '95 and later.

Funky CELs are not all that uncommon. I have an 01 Subaru that pops on and off an O2 sensor code from time to time even though nothing is wrong.