Hello there,
I own a 99 2.3L millenia with 165k. I actually have 4 codes right now. P1743, P0170, P0173, P0300.

Aparrently the code P0300 is caused by oil leaking into the plugs according to other threads.

P0170 and P0173 are fuel trim leaks. But where do I start to find the leaks? Should I have a mazda dealer do that or is it possible for me to fix?

P1743 scares the crap outta me!! I know its the torque converter clutch solenoid circut and that it deals with the transmission. Themillenia shifts fairly smooth other than the common 1st to 2nd gearjerk.The total replacement of the parted was quoted $3300 parts and labor.Could it bea specific part of the solenoid that is malfunctioning that causes the code? What are the common scenarios and fixes for this code??

Any help would be appreciated
Brendan

 

0300 is random misfire. i would first change plugs. dont go for any buttco plugs like iridium. use factory recommended plugs. and PROPER gap. contrary to popular belief, a -11 plug is NOT proper gap. for example, an NGK PZFR5F-11 is NOT correct. a PZFR5F is. the -11 after the number means the gap is 1.1mm, far too big for the 2.3. dont let the parts store person con you into getting a larger gap plug, and then regap. both ngk and mazda tell you NOT to regap. if you get some whacky plug, you are on your own. 0170/73 is classic vacuum leak(s), most likely is 1 or 2 vacuum tees. there are several in the vacuum system, but iirc, only 2 are really a "T". the others are more like Y's. one T is accessible near where the intake piping starts to split after exiting the compressor, but you probably wont be able to locate it till the intake is off. the other is not. you will have to remove the intake, starting with where it exits the compressor. if you are mechanically inclined, what i would recommend is to remove the intake, which involves not only the intake, but both intercoolers, too. to get the rear intercooler off, you gotta pull the battery. dont bother trying to loosen the abv, leave it on, disconnect the vacuum lines, and pull it with the intake. you will then have access to both tees, plus almost complete access to the coils/spark plugs. pull the egr valve, the solenoid assembly off the rear bank, and you can get to all the plugs. be prepared to clean oil out of some of the wells, it seems like all the 2.3's i have ever worked on have oil in #'s 5 and 6. if you dont have access to air tools, you can use the spark plug socket to clean the oil, just keep dipping it and wiping it, till it is near clean. if you pull out the plug with oil in the well, guess where the oil goes? mark your coils, move the rear ones to the front. heat is the enemy of coils, and the rear bank gets way more heat than the front. watch out when removing the connectors from each coil. there is a tab you press down on to release the connector. this clears a raised notch on the coil, and if you are not careful, you will break off the notch, then when the connector is reinstalled, it will not lock onto the coil. i always replace the spring hose clamps with norma type clamps, but i have a huge selection that i get from bmw. i also replace the spring clamps on the intercooler connections with some special wide ones(not T bolts) that i used on my mitsubishi turbos. makes going back in later a lot easier. that should take care of 0300, 0170, and 73. for the 1743, i would first pull the connectors, inspect, then clean and reconnect them. also, clean and reconnect all your grounds from engine to chassis. that seemed to have worked the only time i ever encountered the 1743. the next step would be to probe the connections, and that can be expensive. just throwing all new parts at it could also be even more expensive, but easier than probing.