This is a 283 bored out 60 over. I replaced the intake manifold about 3 days before the misfire started to happen. I am now thinking I have an intake gasket problem and need to pull it off and reinstall it. I did not put blue locktite on the intake bolts as it SHOULDNT be necessary, but I guess it is for mine. While I’m at it, I’ll check to make sure the valve rods are lot sloppy, indicating a bad valve guide.
I forgot to tell you. When I changed the plug wire ends, I checked the cap. Inside looked good, no burn marks. But on the top, the #2 connection was not gold inside like the rest, it was gray from what looked to be minor arcing.
I would look at changing the intake gasket. What Distributor are you running ? I had a an 67 Camaro that would white fuzz a spark plug every time I drove from the Grand Canyon down off the mountain to Phoenix. Lots of coasting and high vacuum. It sucked oil up from the lifter valley into number 2 cyl . Carried an extra plug and plug wrench because it did it all the time until I changed the intake gasket.
FWIW I had problems with the roll yer own wires, I bought them from Speedy or Summit or Jegs, somebody like that. Maybe I crimped them poorly but I doubt it. If using a high output electronic ignition coil with point type distributor everything has to be perfect. I thought everything was straight, all-new parts, but when I hooked it up to a scope everything was ate the hell up. High voltage is weird stuff, everything has to work together. The secondary ignition always builds up to a certain point before it will jump the gap at the spark plug, if there is a defect anywhere else it will take the easier way.
So, I did an intake gasket test with carb cleaner. Nothing different when I sprayed around every possible contact. Could it be the coil?! My coil is 20 years old and wonder if t just finally went with the other problems I had.
I don't think a coil would muller up 1 cylinder (#2 in your case). Is the ignition electronic? I missed what you may have said it was. If it's points you can have a dynamic wobble that freaks out just 1 cylinder. I went through that just a few weeks ago on an Auburn straight 8 with dual points and a 4 lobe dist cam. It would be out enough on #7 to cause the points to be really tight on a static check. I opened that set up an extra few thousanths and it ran like I added horsepower (which I suppose I did). Also if it's points a bad condensor will jack up 1 cylinder, then another, then another. If it's electronic then all of the obvious and easy fixes won't settle a thing if a module or pickup is fragged. Then again you have this issue on one cylinder. I had an O/T small block with a manifold design issue. When cold it had a dead hole, once up to temp it was much better. I chased all the plug/wire/ignition suspects I could imagine. Turns out that 1st 2 years had a really bad intake seal issue under the manifold. It explained the oil consumption too. For such a new car it used an unusual amount, about a qt between changes which I did every 5K miles. I installed an aftermarket set of Felpro manifold gaskets with the raised blue seal above and below the flats of the main gasket. It was nice to finally feel what an LT-1 was able to do. So what's the cryptic message in all those words? Your intake leak may indeed persist, UNDER the manifold in the valley. How to check it is open to opinions, but if you sealed the front with a nice bead of silicone instead of the cork or rubber (the only place I'll use it, normally) you might be able to needle through it, then push the straw from the carb cleaner through there and give it a really light spray and see what gives. For safety's sake I'd probably remove the fan blade so only the crank pulley is turning. The info that says it's worse once warmed up sends me there. Good luck...
I could tell you a story about brand new faulty plugs and wires causing an entire engine rebuild. Actually it was caused by assumption and poor methods. When a new problem shows up, go back to the last thing you fixed (look in the area you were working)
^^^^^ Exactly. To add. Never replace a bunch of different parts at one time toward a single problem. Why? If the fix does happen, what exactly fixed it?
Ok, I feel so sheepish right now. The passenger side intake up front has a small coolant leak coming out of it. I always thought it was coming from the coolant system hose right next to it on my manifold. This tells me that the intake gasket is not sealing and needs replacement. It would definitely explain the timing of the issue like another member here reminded me. I am going to have someone else take a look as well. I honestly had no idea that he coolant would have been coming from the bolt instead of the coolant fitting. I got so focused on plug wires and the electrical that I totally missed an OBVIOUS clue.
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