Rough Running...Ideas

[Anonymous]

My '78 Monarch has begun to run roughly, a condition that seems to have come on gradually over a period of a few days. Idling in park, it feels rough and just doesn't sound right. Putting the car in gear and keeping my foot on the brake makes the condition even worse. My fiance said it really felt like it was going to stall at stop signs and lights yesterday. Now, as soon as you press down the gas pedal even just part way, the problem seems to go away and the engine runs normally. Also, when idling, there is a noticeable hint of smokiness coming from the exhaust pipe. Not a choking cloud, but a noticeable coloration in the air...a bit brownish, perhaps, at least that is how it looked in the light of a flashlight tonight.

Any ideas on what I might want to check first? I am hoping to have the problem diagnosed and fixed tomorrow, but we'll see if I am that lucky. Any time you can save me by pointing out what might be the culprit, and what solutions might be, would be greatly appreciated.

Oh, plugs and filters and oil are all new, as are the cap and rotor.

Thanks in advance.

Dave

 

[Stubby]

I would hunt a vacume leak, and check the idle circut.

 

[MustangSix]

I would look for leaks as pointed out above, but it may also be an issue with dirt or gumminess. Get a can of spray carb cleaner. Run the car at a very faast idle and spray down the inside of the carb, working the throttle and making sure the engine doesn't die. Use the whole can.

That should clear the idle passage below the throttle plate and some other sensitive air and fuel openings.

If the problem persists, then we can look for other problems, like maybe bad compression on one or two cylinders.

 

[cfmustang]

If there is something in the carb, you can always try the poorman's method of clearing the passages.

With the air cleaner off, start the car and open up the throttle in park. When it is running at a pretty good RPM, slap your hand over the top of the carb tight to create a pretty high vac situation inside the carb. That can sometimes blow any junk through the carb.

 

[Guest]

Did it get alot cooler where you are? Try tuning the choke.

Air/fuel ratio is important.

 

[Guest]

If the smoke is black, youre running rich. Thats not good either. A/F ratio.

I say that choke flap is either too open or too closed. Give a try at tweaking it.

 

[Anonymous]

Bad plug wire or crossed plug wires?

 

[Anonymous]

how new are the plugs? if u've had em in for about a week then check em out and see what they look like, white and your too lean...crusty white, too hot...bit brownish is normal...blackish is oil or gas (smell it)

u said it was gradual...doesnt the timing chain gradually go (not sure...thought i heard that before)

check the hose for the tranny, it might be leaking where the little canister thing is on the transmission ( i had that problem on my monarch before and i didnt check it there at first cause its only like a 2" length then goes to steel and then hose again) also had a leaky brake booster hose.