Hi peps,

It's good to back after a long hiatus from hcf.

So here's the deal.
1. Engine check light came up
2. Looked & found corrosion on the bending part of the exhaust pipe just under the headers.
3. Went to shop & got it welded for $35
4. Chklight still up
5. Figured out it was P0131 - 02 Sensor Circuit Low Volts, Bank 1 Sensor 1 (btw the engine & cat)

The question.
1. What could be the reason(s) for exhaust pipe btw the header & my primary 02 sensor to corrode? The guy at the shop said that the excess fuel to the cat can crystalize the pipe and corrode. (Mind you this guy wanted to do a $1000 job replacing my whole cat & sensors; w/o even pulling out a diagnostic tool...fool!)
2. Could there be header crackage? (I sincerely hope not..)

I'm planning to do replace the primary 02 sensor tomorrow morning so any ideas from people who have gone through something like this would be appreciated.

Thanks.

 

Sounds like it's just a case of a fouled sensor.
when was it last replaced? how many miles (est.) are on the current O2 sensor?
Is your gas mileage terrible and do you have hesitation?
when was your last tune-up? simple tune up or the all out tune-up?

just some questions to speed up the diagnostic process

 

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Holy Shizzer...
I may have found what is going on..

While doing an oil change this morning, I found my head nearly hitting the cat converter.
Then it hit me.
The cat was in the wrong place! Instead of being away from the engine & under the passenger seating, the cat & muffler was literally reversed! This car was a lemon and I went as far as almost suing the smog testers that approved the vehicle. They replaced the headers to stock (aftermarket was not LEV compliant-damn u dmv[>:]!) and I called Injen to get an air-intake sticker (can't believe it's not legal w/o a stupid sticker).

Long story short, I bought it at 100k miles, no logs from buyer other than some lame bestbuy cd player receipt, i was in a bind to get a car asap. (NEVER buy last minute like me!!!)

I'm at 117k, getting 28ish miles per gallon; not so great for a 4-banger, and i'm guessing the 02 sensor & cat haven't been replaced before.

Any suggestions?
I'm thinking of having another autoshop cut and reverse the cat & muffler,
then see if the check light comes out; replace the 02 sensor from there onwards.