Chasing a misfire on D1
OK, first of all - I want to THANK everyone on this forum, you all made my Summer project much easier!!!
I was "given" a 1997 D1 with 137k miles on it by a "friend" of mine, it was sitting on his lawn for 3 years. I have a 16 year old son and we spent the summer rebuilding it. (brake rotors, pads, exhaust, plugs (2x), wires (2x), multiple oil changes (sitting oil was gunked up), seafoam treatment, battery, pcv valves, MAF cleaning, throttle body cleaning, multiple interior cleanups, etc...
As of now, it is all running and running almost well. Through the summer, at various stages, I was getting multiple random misfires. After a few oil changes, some aggressive driving, changing plugs and wires twice (because I did not read enough the first time, here is where I am...
I have Champion copper plugs (I think 322) and Kingsborne 8mm wires. All checked, re-seated, etc. I can drive the car for 100 miles on and off the highway with no issues. Then, I will get the check eng light back on. P1316, P0300, P0305 show on my reader. I can reset the light and drive for a while but it will happen again. Always Plug 5. I pulled Plug 5 and it was wet with fuel one of the times. I dont have any other issues, no smoke, not any bad smells, etc.
I brought it to a "real" mechanic and he did some addl testing, checked compression for that cylinder, said it was 140. He did not check others for comparison, I can do that this weekend. His opinion is that the coil might be bad, he thinks that it is not getting spark intermittently.
When the code is not being thrown, the engine is really smooth. Between the recent multiple oil changes and the seafoam via brake booster vacuum, there are no ticks or pings, it is very smooth and starts instantly, etc. Even when the code is lit, the engine is smooth. I might feel a little stutter occasionally but it is hard to tell.
If it weren't for the code, it would be great.
My thought is to get an Ebay coil pack and give it a try. They are $50-$75. I know it will be used, beat up, etc but my theory is that it is not likely to have the same error as mine (if it is at fault). If #5 did not code out, then it points to the original coil pack. If I get lucky, I have solved the problem for $50. If there are other ignition problems but not on #5, then I know to get a new coil pack.
First question obviously is does anyone have any suggestions? Am I correct in thinking that coil pack is the next place to look.
Second question is, if I replace the coil pack, do I need to do anything else? Timing, etc? or is it a "replace and drive"?
This might be stupid, I might be overlooking something simple, I am learning as I go...
Any help will be much appreciated.
Thanks a lot!