Okay so my 292 has always had an inconsistent misfire (I think) at idle, and it runs kinda rough. I can hear quiet random popping coming out of both exhaust pipes, and the motor will idle really smooth for a moment, and then bog down a little for a second and then come back up. It also makes the entire truck rumble a little when it does that. I ran a compression test tonight and all cylinders were within 10 psi of each other with the highest reading at 150 on #5 cyl. The valve lash is set correctly. Then I checked the spark plug wires by turning off all the lights so it was pitch black, firing it up, and looking for little blue sparks or glowing from the wires. All were fine. (They are new wires after all, along with the plugs.) Oh, and by the way, the radio has some static at idle, but goes away at a higher RPM. The misfiring/popping also seems to go away at higher RPMs too, which might have some link between the two... I'd like to get this fixed so it'll run smoother, idle better, etc. etc. duh! Anybody have any ideas or advice? All help is appreciated. Thanks! --Matt
Oh yeah I'm running a Pertronix Ignitor I in the stock distributor and their Flamethrower I coil too... It's a stock motor except the Pertronix and headers...
The only thing I can think of off the top of my head is to check the lead going between your points and the coil to see if its worn or loose. If you're running vacuum advance it could be building vacuum shorting out misfiring and on an on as the advance plate cycles. It could also be carburetor related. Using a vacuum gauge or watching how the fuel atomizes out of the boosters at idle might give you some clues as to what's going on too. Good luck.
I was having some what of the same problem with my 292 in my fairlane. I rebuilt the carb and the intake gaskets were waay gone so I replaced them and it idles fine.
Sorry, I type slow. Now I see you have a Pertronix kit. Another thing you can try is hook up a timing light and check what the spark is doing when the engine misfires so you can see if the ignition is the problem.
The carb and intake were completely rebuilt, and then re***embled together and bolted back on the motor with fresh gaskets. It doesn't leak. I have a vacuum gauge in the truck and it is completely steady at idle (no fluctuation), and moves smoothly when you're driving. It would bounce around if I had a leak right? That's a good idea about the timing light test. I think I'll try that tomorrow. Thanks guys --Matt
The vacuum gauge won't give you an accurate "real time" reading if you plumbed it with a capillary tube. They only work properly when connected to the intake with a vacuum hose.
It is hooked up the right way. I hooked the clear tube that came with the gauge directly to the vacuum port on the intake. From what I can tell, it has a pretty accurate reading.
This is what ****s when they never check back in and let us know what fixed it. All of the posters time to diagnose and help @Mattilac and he does not have the courtesy to respond with the fix.
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