I just used a can of Gumout Combustion cleaner to maybe gain some MPG and while spraying the whole can in (at 10 second intrevals) the SERVICE ENGINE SOON light came on, after following the directions on this site to do 5-10 WOT upshifts it threw codes 12 and 33

12= Problem with the battery connection. Direct battery input to PCM disconnected within the last 50 ignition key-on cycles.

I didn't disconnect the battery, why a code 12?

33= Air conditioning clutch relay circuit. An open or shorted condition detected in the compressor clutch relay circuit.

My A/C hasn't worked in who knows how long but why is it just now throwing the 33?

*EDIT*
On the first tiny spray of cleaner the car sputtered and stalled, then keeping the butterfly open some and the car revved up I got the whole bottle through but the car was stumbling, popping and crackling horribly. Then ran rough for a couple minutes of driving. After some good ol' flooring it runs good now. But should the car have really stalled and stumbled like it did? My car does get poor mileage (230 per tank), I'll be replacing my upstream O2 sensor too but this cleaner only supported my hunch that it is running rich.

 

Yes, the car will run like crap and stall out anytime you pour or spray a liquid into the intake manifold. Basically, what youa re doing is flooding the combustion chamber and intake manifold.

As for throwing codes, I have no idea why its doing that. A code 12 is usually going to always be there. Its nothing to worry about. As for the code 33, beats me. I've never heard of anyone having this code up so thats new to me.

 

My A/C doesn't work but beats me why the code is on

 

are u supposed to spray the whole can in? Whats it do?

 

Yes, you are supposed to put the whole bottle in.

It cleans the carbon build-up off the intake runners and throttle body, ti will also clean the combustion chambers. The best way however to clean the throttle body is bench cleaning it.

 

And since bench cleaning is not an option for me a trip to Pep-boys was in order.

After putting 75 miles on tonight I have noticed a smoother idle and smoother all around (not by a ton but its noticable) and instead of the gastank being empty at 230 I'm at 245 and have a little bit left. So for $3.99 its a good idea.

I'll reset my PCM tommorow and see what happens, my dad thinks we "confused" it. Ehh.. hes wrong.

 

Why is bench cleaning not an option? You don't have a few hand tools lying around?

 

i don't really know what bench cleaning is. Explain

 

Its where you remove the TB from the car and clean it outside of the car.

 

What do you reccommend for resetting the PCM. Neons.org says pull the cap off the PCM and R+R a 20A fuse (leaving it out for 30-45 seconds) and someone else said R+R the fuel pump fuse.

The fuel mileage has gotten better though. On a trip this weekend I got 320 on that tank, about 26mpg.. not bad but there is more improving to be done.