Can anyone help me out??? I have a 2000 Mazda millenia S and it is running like s--t. It run's hot every once in a while and when I'm on the highway driving aprx. 65 miles per hour it is sputting/missing almost like gas isn't getting to the right place. I had radiator changed last week because they found a leak but it's still running hot, the only thing that has stopped since I changed the radiator is I'm no longer losing water. I went to a local shop and they ran codes and what showed is PO115, PO431, P1790...the guy told me he doen't work on this car so I'm stuck....don't know what to do. Any ideas what those codes mean? Also, TCS/OFF TCS/ON light comes on every blue moon.. Sometimes only TCS OFF, sometimes both, sometimes none...

 

0115=engine coolant temp circuit malfunction
0431=left bank warm up cat efficiency below threshold
1790=throttle position sensor open or short

tcs off/tcs probably because of the 1790. engine sputtering and rough could be 0431, the cat is so clogged, it is not flowing, and you got tremendous back pressure, which also can make it run hot. and, after a while, it can make it stop running. forever

 

I brought it to muffler shop to have the catalytic converter checked and the guy check it and also for an exhaust leak and told me the catalytic converter is clean, it looks new... i'm so confused... I'm a female going through a divorce so I'm lost, don't know much about vehicles. He didn't even charge me so I wouldn't think he would lie to me... What u think? Also, the guy I told you checked the codes yesteday said he didn't know much about this vehicle but he said he thinks it's a head gasket, what you think? My dad said he thought it would do it all the time...

 

the overheat could very well be a head gasket, or a crack in the head/block. and, answered in the other post, the muffler guys dont know where to look. if the pre cat is clogged, it will throw the code, and then it gets worse, and you can get engine damage. which might be where it is now. a leakdown or compression test will tell you if you have leakage, but on that car, it is a real pain to get at the spark plug holes. if you do get one done, i would recommend the leak down over the compression test, it is a lot more accurate, but costs more. the sputtering and running like crap is even further indication of one or more bad cylinders. losing coolant is another indicator. be VERY careful from here on. this could be VERY expensive, and you will never recover your cost.

 

Thanks so much for your info. It's my fault because I didn't have the print out form the shop when I went to the muffler shop so I told them wrong only because the shop that ran the codes told me it was a exhaust leak or a faulty catalytic converter so I told them both those. now I know to go back and explain what you said!!!! Also, with the head gasket thing, don't you think some code would have showed that? And, doesn't water mix with the oil when that happens? I'm just trying to figure all this out because if its going to cost a fortune to fix, I'm done!!! It's a 2000 with 110,000 miles. It's not worth all that money!!!

 

when a head gasket blows, or a crack in the block/head, different things can happen. the gasket can blow between the cylinders, in which case no coolant will mix with the oil. the gasket can blow and/or crack btwn the water jacket and the cylinders, so no mix with oil there, either. it is very difficult to diagnose, and would cost a couple hours labor to find out. assuming the worst, the engine is bad, probably the most cost effective is to install a used motor from japan. i have seen them on ebay for 900 bucks. add on labor, and probably 2500. however, since you have to depend on others to repair your car, i would advise getting rid of it. in top shape, it's only worth about 4k in the open market, maybe less. these cars dont have any resale value