Originally Posted by Popsy
Originally Posted by irv
I honestly don't think, but could be wrong, that if it were a bad coil, the car would still run on 3 cycl's?
When you say cold joint, are you referring to a split/chafed wire somewhere or something else?
If the coil goes bad, yes.
In my case (just referring to what happened to me lol) the coil wasn't "bad" per se (as not producing high voltage anymore), just sometimes internally shorting, I guess (not really sure how a coil works) shorting the high voltage side to low voltage side, which was temporarily confusing the ECM when the tension spike was happening. The problem was also worse with humidity (Brittany, humidity is almost always high) and heat.
Cold solder joint, usually in one of the electronic units ? Could be anywhere, really wild guess here. Could also be a chaffed wire somewhere...it's difficult to pinpoint. If you've checked all the major electrical connection, plugged/unplugged the ECM several times to remove any eventual corrosion, then I don't know what else to do, except data logging.
If you have a scanner with live data capability, maybe you can try to have someone driving while you look at it and pray problem happens to spot any off chart data at that moment ?
Also I don't remember, did you change the spark plugs, or just inspect them?
I replaced the plugs with new ones. If I had to guess, I'd say this car still had the originals in it?
Furthering my thinking here, can a dirty or defective throttle body and/or its electronics maybe cause this problem? I just came back from another test drive and when the car was barely warm, it stumbled on me as I was leaving a stop sign. It didn't stall, just a stumble like it was going to then ran great.
When I have had his engine cover off, I have noticed some soot built up down in there. The procedure for cleaning one is just to use a rag with the product on it, (no direct spray) but that would only clean the front side of it, not behind the throttle plate. I assume anything is better than nothing but will this really do anything?
To remove it and clean both sides, I have read where the computer will have to relearn everything but the only, proper way, to do that is to have a dealership do it for you?
I know I am drawing at straws, but, imo, it is something to consider??