I have had an issue with code 42 popping up occasionally, even had it stall out completely a few times. It has a brand new ESC, coil, I had the ign module tested several times and it checked out ok, cap and rotor arnt old but not very new either (ill explain in a minute).

I have noticed that sometimes when I hit a bump in the road ill lose some power, it'll feel much weaker, then it'll come back to life. It usually will also flash the SES light, sometimes the light will stay on.

The last couple days its felt weak. Almost like a v6. Last night it stalled out completely, i pulled over and ran the codes, 12 & 42. After, I started it up and it started up real strong, and had all its torque back. I actually burned-out on accident because I was so used to the lack of torque that when it all came back I forgot how powerful it was! Now, its back to v6 power.

I think it might be a bad ground, but im not sure where. I have tried checking the grounds on te pass cyl head but didnt see anything wrong. Are there any other grounds to check?

Could it be a sensor going out?

I noticed that when i took my cap off there was a scratch inside. I talked to a freind of mine thats in his late 60's and has been building race engines for about 40yrs, he said the rotor could have gotten lose or that the shaft may have too much play in it, or the bushing on the bottom towards the gear could be messed up. He said that if the rotor isnt lined up with the terminals on the cap properly, it would cause a lack of power like I have too. Either way, I know there should be no scratch there. I took the rotor off, cleaned it and the inside of the cap (black dust from the rotor scratching the cap) and put the rotor on again, after putting it all back together and starting it I had all my power back immediatly and it lasted a few days.... The cap and rotor are Accel, and I got them from a junyard. They were on a 3rd gen and looked brand new, so I got the 2 for about $5. Im not sure if the rotor was or got damaged before installing it, but i think that the scratch on the inside of the cap may have something to do with this.

Thanks for the input everyone.

 

Yesterday I took the cap and rotor back off, cleaned them, and put them back on. They werent horribly dirty, but they were dirty. The cap looked the same, i didnt see another scratch. The one that is there is big enough to hook a fingernail though (it may be getting deeper, not sure). Its right on the inside wall of the cap. I noticed a black "singe" mark on the rotor, in the middle. Is that normal?

It started right up and ran strong again. took it for a test drive and it seemed right back to normal. Just now came back from work and it took a bit of cranking to start, and when it did it felt and sounded weak again. I drove it home and it started raining, and it got noticeably worse. The SES light came on, but went back off after about a minute. It flickered on and off a few times too. I parked in my driveway and noticed that it was idling poorly, it idled at close to 1000 in park, but would sink almost to the point of stalling (~500-550) before the computer saved it and it went back up to about 1k. It did it if i revved it and let off the gas too, didnt rev as powerful as normal and even sounded different, as soon as i let off the gas the rpms sank down to abt 500 before the comp jumped it back to 1000, and it kept doing that.

Im not sure if that was moisture under the cap, but that wouldnt explain why it runs weird when its dry out.

Any ideas?

 

I think you need a new cap and rotor for starters. That "scratch" may be a cracked cap.

 

BTW on your first post you mentioned code 12 too, remember that code 12 is the diagnostic mode. Anytime you are retrieving codes from the ECM it will display 12 three times before displaying the problem codes. That's normal, code 12 is not a problem code, just letting you know the ECM is in diagnostic mode.

 

did you ever figure out the problem? i also have code 42 coming up when i start my car and it idles poorly. it does not happen all the time but when it does the car drives pretty rough.

 

code 42 means that the ECM has found a short in EST, ground or bypass circuits.

 

@ T/A thank you. would you be able to explain how i would go about finding the short?or what i am looking for? am i looking for any loose ground wires? this is the first issue i have has with anything electrical so dont know where to start. thanks for the help.