94 MX-3 V6 1.8L Engine stumble

[shlepadoodle]

Problem started with this severe cold weather. The spark plug wells filled with oil so I had the seals replaced. I replaced the pcv valve, distributor cap, spark plugs and wires because it was needed anyway. At high speed engine works fine but when I rev from idle it stumbles and hesitates until it gets the revs up. It idles smoothly but frequently it will pop in the exhaust like it is missing. I haven't done the engine code yet until I get more info. Seems like the manual disappeared from here. Could it be a bad injector and if so how do I determine that?

[masonholmes]

I've got exactly the same problem, and have a CEL.. Checked the code, (sorry, can't remember), and it was a knock sensor code. My knock sensor is bad and thus the engine is running with retarded timing until it hits 4k RPM and other devices take over where to put the timing. The most common reason for a bad knock sensor is a bad ground/wire going to the sensor. I replaced my sensor, (with a used one that at least WAS good when it came out of the 2.5L, lol), put everything back together and still had the code. Dunno what's up - but am taking care of it with a 2.5L swap, lol. Good luck..

[masonholmes]

Oooh, somthin I forgot to say.. You replaced the rotor/cap, but this may be early warning signs of the distributor going out. There's a specific part in them that fails due to excessive heat, over time - the ignitor module. It has given these distributors a rep. for failing. Some people get warning signs, such as stumbling, and other times they just cease to work all at once.

[shlepadoodle]

It's a possibility that it could be the igniter module however I am going to do more digging before I spend more money which is very easy to do on the pricey parts for these cars. Reading at another site for Probe the engine code 12 points out that the TPS could be the culprit. I am not sure if I can use those fault codes. Does anyone know where I can get the fault code listing for this engine. (Don't want to freeze my *** off checking wrong fault codes!!)

[andy]

sounds more like a crack in the plastic intake just before the throttle body. to check for cracks its best to take it off. if you find any,
wrap it with duct tape or equivalent.
Andy P. 93 GS

[shlepadoodle]

Originally posted by masonholmes:
Oooh, somthin I forgot to say.. You replaced the rotor/cap, but this may be early warning signs of the distributor going out. There's a specific part in them that fails due to excessive heat, over time - the ignitor module. It has given these distributors a rep. for failing. Some people get warning signs, such as stumbling, and other times they just cease to work all at once.

Checked the engine codes and they were clear. Took it to a Mazda dealer and they checked the fuel pressure and injectors and they were ok. They concluded it was the distributor. Sure enough that's what it was. You were right. Thanx