recently my 2003 mazda 6 2.3 lt has been idleing rough -- had codes checked and it is running lean at idle -- drives fine at a good rate of speed but when turning it has started to die. Replace the mass air flow sensor and still doing it. Check engine light even went off but still running rough and backfiring. Any ideas on what else we can do to fix this thing without having to take to dealership. Also have checked hoses and can find no apparant cracks. Live in a small town and closest dealership is 70 miles away so not sure if the car will even make it that far.

 

Hi there, How do you know the Vehicle is running lean? Do you have any Fault codes to say the vehicle is running lean ? Ok Firstly spray some WD40 or brake or clutch cleaner around the Inlet manifold area and around by the Injector seals , If the engine note changes , this will indicate a leaking inlet manifold gasket or leaking injector seals . Let me know how you get on .
Secondly, if there are no leaks Inspect the fuel rail pressure damper vacume hose for signs of leaks or cracks , actually disconnect the hose and see if the engine speed fluctuates or stays the same , also make sure no fuel is coming out of the vacume hose.
You may have a fuel pump fault , the only real way of checking the fuel pressure is to connect a pressure gauge in line of the fuel circuit or use a live P.I.D inspection using a Diagnostic tool.
Try Disconnecting the upstream Ho2s sensor and see if the running of the vehicle improves ,. Ok Make sure you let me know what cured the fault ok.
Good luck.

 

We had this same problem back in june -- took the manifold out and put new gaskets in it. Afterward it was still idleing rough. Sprayed the cleaner on it and it did get better though started up again after a few minutes. Took it out and drove it hard and engine light went off and everything was good for about a week. That's when the engine light came back on-- still running fine though. This past 2 weeks the idle has slowly gotten worse again and the backfiring started. And it is now dying when turning or stopped at red light. That didn't happen back in june. We had it hooked up to a computer and the codes told us it was running lean. Said the barometer reading was high . That is when it was decided that is was the mass air flow sensor. When it was unplugged the idle was high at first then went normal after about a minute. Didn't run worth a flip while it was unplugged though. Felt bogged down. Am going to inspect the hoses better and see if that is what is doing it. And will check the fuel pump. Thank you for the advice-- very much appreciated. Any more advice will also be appreciated

 

Spray the brake cleaner on all hoses and also on part of the manifold. Ran smooth on a few spots on the manifold. Since it has new gaskets on it, would this point in the direction of the manifold being cracked? Do you happen to know roughly how much one would cost if i install myself ?

 

Yeah to me it sounds as though you have found the fault my friend a crack in the manifold , Good Job , im not sure how much it would cost , go to a mazda parts department and find out., Might be expansive It might be a good idea to replace the injector seals too. Is the vehcicle a 4 cylinder?. Glad i could be a help.

 

Well looks like we may have hit a break on this one -- taking out the manifold off -- found a pvc hose on the underneath that was busted -- got a new one put on but in process have somehow blown the main fuse -- rigged it up for a second though and in that sec the car ran great -- now just gotta get that new fuse on and we will be good hopefully. Again thank you for the help !!