Replaced the plugs and coils on the '17 expedition. Went NGK and Hyundai. Gaps were 0.05 out of spec more or less, so they really needed it. The coils were probably OK but I couldn't remember if I had replaced them ever and if they are factory, 300,000 miles is asking a lot.
I hate those clips on the coils. When they work, they're fine, but if they hang, it is super easy to break them.
Also replaced the plugs on the Nissan, including the infamous #6 plug. I think the distributor actually spazzed out, but seems to be operating normally again now (common issue in VG33 motors), but I decided to replace the plugs first since they were badly overdue. #6 up against the firewall has to be done completely by feel and by using a specific combination of wobble extensions. I think the damn crush washer came off against the block, so now it has a stack of two, possibly. The other plus are in deep wells but easy angles to get to. The only problem is if the washer comes off the plug and sticks to the recession in the block. You have to use a mirror or in my case a pipe scope and a piece of coat hanger with a little hook bent into the end to pluck it loose and fish it out. That seemed to go ok as well. That whole set of old plugs also had oversized gaps and did need replacing.
I may and up having to replace the distributor also if the misfire returns. I had a P0306 which is cyl 6, but it also threw a P0300 pending code which is a random multiple. It could be a sign that the internal bearing or the optical timing sensor on the distributor is failing. The bearing is actually serviceable with care for the price of a small high quality sealed bearing. The optical sensor is pretty much impossible to find as a separate purchaseable part, unfortunately, so if it is that, it needs a new distributor.
I hate those clips on the coils. When they work, they're fine, but if they hang, it is super easy to break them.
Also replaced the plugs on the Nissan, including the infamous #6 plug. I think the distributor actually spazzed out, but seems to be operating normally again now (common issue in VG33 motors), but I decided to replace the plugs first since they were badly overdue. #6 up against the firewall has to be done completely by feel and by using a specific combination of wobble extensions. I think the damn crush washer came off against the block, so now it has a stack of two, possibly. The other plus are in deep wells but easy angles to get to. The only problem is if the washer comes off the plug and sticks to the recession in the block. You have to use a mirror or in my case a pipe scope and a piece of coat hanger with a little hook bent into the end to pluck it loose and fish it out. That seemed to go ok as well. That whole set of old plugs also had oversized gaps and did need replacing.
I may and up having to replace the distributor also if the misfire returns. I had a P0306 which is cyl 6, but it also threw a P0300 pending code which is a random multiple. It could be a sign that the internal bearing or the optical timing sensor on the distributor is failing. The bearing is actually serviceable with care for the price of a small high quality sealed bearing. The optical sensor is pretty much impossible to find as a separate purchaseable part, unfortunately, so if it is that, it needs a new distributor.