Changed O2 Sensor, Still engine code... Help!

Okay, I was getting terrible gas mileage, and I was getting a code 44 (lean exhaust) so I replaced the O2 sensor. Now I'm getting a code 13, which means the oxygen sensor is shot. I checked all connections, and everything seems good. What could be the problem now? Any help would be appreciated.

Oh, and also I got a code 45, which means rich exhaust. Could my ECM be at fault? Maybe the mixture control solenoid is bad.... how would I test something like that?

Maybe post year and engine info it sounds to be a pump issue check fuel pressure we are shooting in the dark with no year or engine info

Oh, sorry... Its a 1984 caprice, w/ a 305. 4bbl rochester q-jet carb, Canadian emmissions. Also, lately, I've literally been getting 5-8 MPG, and I have less power than usual.

Anything, anybody? I've driven a total of 20 miles this week, and used up more than a half of a tank. Please help. Its never been this bad on gas before.

What type of preventive maintanence have you had done?

A fuel induction system cleaning probably will help, especially if it has not been done for a while. Another option would be to use the SeaFoam or Top Engine Cleaner we've mentioned in other posts.

Have you had a compression check done to see if you have good compression?

Also, when's the last time you had a tune up performed? Have you had your ignition timing checked?

All of these things might contribute to poor performance. I'm sure the other guys on this forum have other ideas to offer.

The timing is at 6 degrees over top dead center with the computer unplugged. The last tune up I did was about 4000 miles ago. I changed the plugs (AC Delco Rapidfire plugs) and got a more powerful ignition coil. Also, I replaced the fuel filter, anmd removed the carburetor and cleaned it out by blasting it with carb & choke cleaner. Recently all I've dont is replace the O2 sensor. As for preventive maintenance... All I've done is replace any cracking or stiff vaccume lines, replaced the spark control module, cleaned the pcv valve (even though it was working properly), checked the smog pump and all the lines (found a leaking one, but I fixed that), and now that I think of it I should really get a new air filter. I'll do (or get) a compression check done. Thanks.

Timing 6 before top dead centre with the 4 pin connector at dist disconnected right??? Did you adjust your float or pump when cleaning new gaskets?? Hoses routed right on vac spark control

When you say float, are you referring to the carburetor? Actually I just finished rebuilding the carb today, and adjusted everything to specs (float at 11/32), replaced all gaskets O rings and seals, gave the main body, base and airhorn assembly a bath in parts cleaner.

Okay... now that I've rebuilt the carb, the car is running amazingly good (incredibly responsive, doesnt take much at all to get it moving), but one problem. Now instead of a rich exhaust code (45) I'm getting a lean exhaust code (44) along with the faulty Oxygen sensor code (13). I get the code literally every time the car sits at idle for more than a minute. Could it be that I need to adjust the mixture on the carb? I thought the computer took care of that though.

I would say if you richin your mixture a bit and disconnect battery pos cable a minute[to clear codes] you would be all fixed up seems your running lean or battery not up to snuff The battery is the weakest link in computer controlled cars