i appreciate that you are doing some of your own work and want to expand into drive train repair but these type of problems require proper equipment, knowledge and diagnosis. We are glad to help but you have to do your part. Your only alternative is guessing and parts swapping which is expensive and time consuming. To make any meaningful progress you are going to need a proper scanning tool and be willing to do some reading to followup on our suggestions. Les can get you set up with the most cost effective scanning capability. Searching here and google will get you up to speed on fuel trims, freeze frame data, etc. In the mean time I have given you some suggestions with water bottles and visual inspection for moisture. That will get you started and its almost free.

George

 

Actually did that today. No reaction from the distributor cap but the wire coming off the coil is arcing all over the place, quite the light show, when moving the throttle by hand when it’s wet the engine started shaking bad, looked like exactly what I felt. The codes are both back as well, random cylinder misfire and catalytic convertor below efficiency. I believe I have found the likely culprit.

I also ran an experiment, before I went out of the driveway today I let the engine warm to temperature, not a single problem was had (other than a kind of rough start).

I’ll be replacing the plugs and wires Monday and see if the issue is fixed. Maybe the catalytic converter will burn the crud out after this?

 

Keep in mind that when you get a code indicating a malfunction that can be a legitimate failure, properly pinpointing the actual failure OR you can have some other issues, chief among them being: bad sensor/wiring/connectors, or a related failure and the code is not the root cause. In your case an example might be a bad O2 sensor instead of a bad cat. Have you measured the exhaust back pressure and looked at the O2 sensor behavior?

George

 

Replaced the plugs and wires today, the wires were so bad one had a hole burned through it. I have noticed a nice increase in power, not getting the sluggish feel now, though the service engine soon light remains on with the catalytic converter code.

I don’t know if the cold start or wet weather problems have been fixed yet, but I’ll find out.

 

Always start with physical inspection of all components related to the failure. Its free and does require fancy equipment. Broken/corroded/shorted wires or connectors, split hoses/cables/etc. Leaking fluids, funny noises, etc.

George

 

With one with a hole burned threw it, you probably were only running on 4 or 5 cylinders!

 

It was actually the wire going from the coil that had the hole burnt into it, not sure about the others, but I was getting a random misfire code, so I wouldn’t be surprised.

 

Well that'll surely mess up your performance!