'78 Creampuff Marquis 460 with a weird miss

[traderssd]

Hi All,

I recently inherited a creampuff '78 Marquis with 80K with a stock 460. This thing has had TLC all of its life. Even so, because of age, I went through all the accessories like carburator, distributor and all ignition components (plugs,rotor,cap,dist. pick-up, ign. coil), belts, hoses, EGR, water pump, etc. I didn't pull the heads but I did R & R the intake manifold and put in a new stock timing chain. Even checked the compression with all in the 130-135 range.

Here's my problem, the thing is a bit hard to start with a rough cold idle. I figure maybe my choke or choke pull-off isn't set quite right. It smooths out pretty good as it warms but still has a weird miss. Even when reving it up, it feels like it's eradicly missing. If I didn't know better, my first impression is to say it has a bad plug or wire but all that is new. I've checked everything I can think of including pulling one wire at a time off the distirbutor (ouch!!) to see the influence. It misses worse each time I do it and runs better when I put it back. Could it still be a bad plug or plug wire. (Just an FYI, I double checked that the timing gear set was set right when I installed it). Just seems more like ignition and not fuel related.

Does anyone have any ideas to share??

Sincerely,
Stuart D.
Portland, OR

[turbo2256b]

Just as a heads up which timing gear did you install? The pre 72 timing gears add a bunch of power. AFTER 72 THEY RETARDED THE timing 8*

[Brown_Muscle]

Just a couple simple questions, by "Went through" I assume that means the carb was rebuilt? Also are you pushing the pedal down before starting it to set the choke for a cold startup? If it isn't set right on startup, and not idling higher until it warms up, it will run rough, as it's a carb'd engine.

[traderssd]

Hello and thank you for the response. To answer both questioins, I put the stock timing gear set in with the retarded 8*. I'm aware of the cold start proceedure to "set" the choke and have verified that it's working correctly. The carb was gone completely through by a vintage carb specialist. I'm pretty sure he did it right as he's known in the area and has an impecable reputation. Even after it's warm, it still doesn't idle real smooth and feels like it has an intermitant bad plug or wire. Any other thoughts?

[Mainemantom]

My 75 460 did the same thing. It was bad gas. After running the old stuff out, I filled it with Premium. Changing the fuel filter and it runs fine.