Misfire problem
Asked by Leo Jan 26, 2015 at 12:44 PM about the 1967 Mercury Cougar
Question type: Maintenance & Repair
Hello all, I have a 289 engine which has been running fine, but in the last couple of
weeks it has not been wanting to idle properly(revving too low). I did an oil and filter
change last week and took it out today for a run. Made a stop and on the way back it
started misfiring upon acceleration. Gentle acceleration was fine but anything more would
cause misfire. There's been no smoke at all but I should mention that the exhaust is
blowing a bit from the pipe conecting to the exhaust manifold. As I say, I have to keep my
foot on the gas pedal at idle to stop it from stalling. Many thanks in advance.
8 Answers
I've had the air filter on and off a lot recently, wondering whether the carbs a bit dirty perhaps? Or something like the coil or dizzy cap, but they look quite new..
I forgot to mention, the idle isn't consistent . It has those starvation signs.
Something you might try. Start the engine when it is totally dark outside and while it is dark raise the hood and look for arcing at any spark plug wires, distributor cap, coil, coil wire and spark plug boots. The darkness will help to spot arcing. If there is arcing at the plug wires replace them. A good read on you ignition system is at the link. http://www.mre-books.com/interchange/interchange7.html
I have considered that actually. Could it possibly be the fuel filter clogged up? As starting the car is a bit tricky even when warm and then there's the smell of fuel after cranking.
the smell of fuel says your getting plenty of gas. Your plugs might not be firing correctly, you may have a clogged air filter choking it out, or your fuel/air mixter is off.It can adjust under normal conditions.
Ladysman, I'm getting the feeling It might just be the carb needs tweaking, I haven't checked plugs yet but definitely not air filter because that's new. I've used it about once a week but each time it been harder to get to idle by itself. Thanks for your input so far.
