Can't find any reference to that in any manual for my truck. Since it's carburated, I may not have that, or it's named something else. I think it might be one of a couple of things. Either I have a leak in the exhaust manifold on the left side (which is where I hear most of the noise from) or the "anti backfire valve" is no longer working. I've got some test procedures for the ABV, and I'll try to get a mirror and look around the exhaust manifold for any signs of a leak.
OK, I still haven't gotten this thing figured out yet, I'm about ready to bit the bullet and take it to a pro. here is a video where you can just barely hear the popping noise (about 12 seconds, 18 seconds, and right at the end) http://www.youtube.com/watch_private?v=Q9jm_gTECU0&sharing_token=51Dadp11g_Bmokr3CMKZUw I pulled the plugs from the drivers side and here's what 3 out of 4 looked like: Here was the 4th, the one closest to the firewall: This one smelled of gas and appears to be "tarnished". Any ideas why one would be this way? Thanks
Wet is usually indication of rich. New plugs, you say, so I'd move that plug to another cylinder and see if it's the plug or cylinder. But check the gaps, they look WAY wide for a carburetted engine. IIRC, they should be somewhere around 35 thou. (Don't take that to the bank, tho'.)
The owners manual, sticker on the hood, and haynes repair manual all say the gap should be .042-.046. These were all gapped out at .045. If the carb was running rich, wouldn't all plugs be the same? I dunno, maybe one of the valves is sticking and not closing all the way?
Usually, yes. Switching the plugs will at least isolate it to one cylinder or that particular plug; if it isn't firing correctly, it will be kinda wet no matter which hole it's in. Laying it on the block is an unreliable test, sometimes (but seldom) they work fine in the atmosphere but not under compression. After that, it could be a valve sticking. Have you used a stethoscope (read as a long screwdriver) and tried to localize the noise?
