Ok, got a strange problem! Some time ago the rotor came loose under my dist. cap and broke the cap and rotor. I replaced the cap and rotor and the car ran fine. However, soon afterwards while driving normaly I would feel the car stumble for just a second and then it would begin to run strange. Within a few seconds the "Service Engine" light would come on. The light will stay on and the car will run, but act strange until I turn the engine off for a minute. When I restart the engine the light is off and the car will run fine again. It may happen again within a few minutes, or it may not happen again for days. Typically now it will happen within 10 minutes of starting the car.

The first time it happened I checked the code and it indicated a code 42. In reserching this code, I'm not really sure what it means. Something to do with an open short in the distributer.

If the car is cold when it happens it will run quite rough. If the car is warm when it happens it acts like it has a miss, but idles and runs fine except when you ease off the throttle, then the engine almost acts like you turned it off and are coasting until the rpm's near idle, when it seems to kick back in. Almost like it has no compression when you let off the gas. Very strange!

Anyway, do any of you understand this code 42? By the way, after the first time I read the code, the service engine light still comes on, but the code no longer registers! :confused: I'm confused. Could something have been damaged when the rotor came off? If so, what?

 

Usually its either the distributor module, the knock sensor, the knock module, or the ECM itself that is the problem.

 

Seeing as you had a mishap in the distributor I would pull the cap off and check the wires inside and change the module. Seems you are Missing pulses in electronic spark timing signal. Maybe something is shorted out in there.

 

Seems odd that it is so sporadic! Do you think that a full blown scan tool would be able to narrow it down?

 

Being sporadic makes me feel as if you have a short inside the cap. If your rotor broke off, it was pretty violent inside. You may have cracked the connector, pulled a wire loose so its arcing. I wonder why the rotor came loose? Hard to tell from here...I am just guessing.

 

Hi, I had the same problem with my 89. It turned out to be the ECM and had it replaced. This happened about three years ago. Since that time, no problems. I hope it is not that, because it was not cheap!

 

I believe the two screws that hold down the rotor simply worked their way loose over time. The engine had not been together all that long, so it's possible that I may have never gotten them tight when I put the distributer in. Lucky it happened when it did...30 mph in town, as opposed to two nights before when I was doing 150 mph at night, with the top down :eek: . Anyway, I looked the distributer over pretty good when I put the new stuff back on, but didn't see any problems. I hate to just start replacing stuff without a better idea what might be the cause. I'm considering just buying a new high performance distributer with new module and coil. Maybe that will cover all the bases!

 

Ouch! I was hoping it wasn't gonna be the ECM! How much is a new ECM anyway? How did you narrow it down to the ECM?