Engine surging and spark plug gap

[2seater]

I mentioned a couple of weeks ago about the surging/roughness at low engine rpm and the torque converter locked up, like 50 mph, and light acceleration. Per some comments about spark plug gap, I removed the 12k mile Autolites and returned the gap to the stock .060". The plugs looked perfect and it reduced the roughness by probably 60% or so. It's much smoother and I do not seem to have traded this for a hi-speed miss under boost. I may still need a new coil pack, but the engine does seem to like the wider gap for firing lean cruise mixtures. Maybe new high dollar plugs are in the future too, although not a great believer in them, but opinions do change

[Guest imported_dantm4]

Really sounds like a coilpack - get a Delco Unit at a "botique de junque", mine certainly likes it a lot better than the old one. Was $50 because they fished it out of the car - but might be able to find one for $40 if you do it. Good luck!

-Dan

90' Black/Tan Coupe

p.s. I'm running Bosch Plat. +4's, they're ok, but probably unnecessary, my car idles smoothly at about 600, and accel. when I need it, and cruising - well it was born to cruise!

[2seater]

I agree, a new coil pack is probably in the near future, and a cruise through the boneyard will probably happen. The wider gap probably only helps the good cylinders in the pack, but then I also have a semi-solid upper dogbone engine mount so I feel more of the engine than normal. The only dislike I have for platinum plugs is the spark always looks "cold" to me. If you compare the spark from a standard and platinum, I have found the platinum tends to look thinner for some reason, although it does erode more slowly and keeps the plug gap within tolerance for a longer period. Have you ever seen a plug with platinum only on opposite electrodes, depending on where installed? My wifes Ranger has a similar ignition to ours and the plugs on opposite sides of the engine were platinum on the opposite electrodes. My assumption is the polarity on the plugs is reversed on opposite sides since two fire at once, like ours, and the erosion occurs primarily on one side, so the factory saved money with the single platinum where needed. It's virtually impossible to find replacements and double platinum is the recommended replacemement. Weird deal. And yes, Reattas excel at cruising.