Let's understand so we don't get you hurt with anything there. You said you were fairly new to working on cars and I want YOU to use all judgement with anything that doesn't make sense or could hurt you and WHEN IN DOUBT - DON'T! Let that be the rule: Ask again or get assistance please. It takes years to just get started with being a technician so don't expect to know everything (none of us could - there's so much to know) about mechanics quickly.
The erratic firing will diminish at higher RPMs. It helps to direct you to the problem area if you can tell if that's random or a single, regular putt or miss which indicates ONE cylinder but let's get started with something.
1. - To test for visable arching is like watching for a spark when there is static and you touch something it goes "tick" and sometimes you see that. Bet most people can relate to that and that's what I'm talking about. The high voltage that makes the spark plugs spark starts at the coil - the item with just one pencil or so size wire and a boot. It's large wire goes to the distributor cap which will have the six - one for each spark plug + cylinder. All the items that control that spark (high voltage!) must contain it till it gets to the spark plug itself where it will make the spark unseen to fire the air/fuel mixture. Ok so far?
2. - This electricity like all is charged to seek ground which the engine is. It doesn't care how it gets there but we need it to do that last jump to ground at the spark plug and not at a weak point in wires or parts along that route.
3. - Spraying some water at one area at a time will encourage the electricity to leap out for ground at that spot if there is a weak spot there. Water other than distilled will conduct electricity. A little salt in it will conduct even better. Good components won't react to being damp. Sometimes you can see it and sometimes not but it helps if you can to isolate the problem area or perhaps rule out this isn't the problem. I say do this with engine on the cooler side as the plastic parts (coil, dist cap especially) don't want the shock of being cold as that could crack a good part.
This is fairly quick and simple to start with. Don't touch the areas as there is always the risk of getting a shock yourself which is surprising more than harmful and to be avoided.
That would be a good start to the testing. Report what if anything is found and note if engine reacts adversly to doing that as that is a strong clue and note where it reacted. If nothing there's more - let's wait till you say what happened.
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Vacuum leak testing: First just look for rubber hoses that aren't right. Rubber can be purchased to splice in a bad area if you find something like that obvious. Some vacuum will go from rubber elbows to plastic line that looks like wire and that gets brittle over time and breaks clean. Those can be patched too.
Further testing using carb spray cleaner with the tube: THIS CAN CATCH FIRE SO USE ALL CAUTION AND BE READY FOR THAT!! Just look at where the air is taken into the engine to a central point on top thru plastic snokeling of sorts to get there thru the air filter. Where the snorkeling meets the metal is the air horn intake and that area and many more need NOT to leak. Carb cleaner when sprayed on an idling engine will alter the idle - it could run better or stall depending. Use spray targeted at one spot at a time and sparingly. Don't let it make puddles. Spray along vacuum lines and the devices they go to. Also spray along the base of that air horn as there is a gasket there. Note where it reacts if it does at all and we'll move on from there.
Hey - have an extinguisher ready or don't do this if you are not comfortable with this.
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The whirring noise will probably require a new starter but if you can still start this let's wait till we getting running well first.
Hit back with questions or results found. Try to describe the area if you don't know the name and I try to find a pic to match what I think it is.
Good luck,
T
Ps: About all the manuals and books are going to be based on you having a good base understanding to start with and if yours has a pic with a name just say the name and I'll find it
Tom Greenleaf - MetroWest Boston - USA
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http://www.autoacsystems.com/tomgreenleaf/