Re: [Chrysler300] poor running car

[Robert Merritt <okbobwynmer@xxxx>]

A few questions. [1] Is the problem worse, better, or the same when first started up cold vs. after warmed up? This will help decide whether the choke is involved. [2] What carb do you have? If its a Holly, was the accelerator pump diaphram replaced during the rebuild? Almost sounds like raw, unvaporized gas might be dripping into the venturi and momentarily flooding the engine, causing it to almost die, then clear itself out until the next drop hits. Try shutting it off while it is in slow idle and then see if it seems to start like it is flooded. Another thing to try is with the engine idling, hold a mirror over the carb and see if you can notice gas dribbling into the venturis. Don't overlook the secondaries on the 4 barrell; the idle mixture is controlled by the primaries but a leak into the secondary venturi's can disrupt the mixture because very little air passes the closed throttle butterflies but any gas that leaked into the back 2 venturi's could slowly leak past the clused butterflies and enrich the mixture.
Have you tried a timing light to see if the ignition timing fluctuates with the idle RPM? It's possible the centrifigal advance mechanism in the distributer is either sticky from not being lubricated ocasionally, [a drop of oil on the felt at the top of the distributer shaft under the rotor], or a broken return spring on the advance weights. this could cause the timing to fluxuate at slow idle but smooth out when reved up, The timing light might show if this is happening. Back in my previous life building cars to race on a drag strip, modifying the advance curve was one of the easiest ways to improve low-speed throttle response, so a problem here can also adversly affect idle and low-speed throttle response. Does the car have good throttle response or does it have a flat spot until it gets going?
A quick way to check is to remove the distributer cap and try to move the rotor in the direction it rotates when running. It should move forward a few degrees without much effort and if the springs are OK they should pull it back when released. 
Hope some of this helps, even if just to eliminate possibilities.
Okie Bob Merritt
Enid Okla.
"my69300 <tubman@xxxx>" <tubman@xxxx> wrote:Hi everyone
It's been a while since I posted.
Here's my problem I have a 69 300 
with a 440 and a 4 barrel-- the car
is and has been running like crap.
The rpm's at idle will go so low
it will almost stall then the rpm's
will return to normal then go back down 
again. It will keep going up and down.
Once I get to the open road it runs great.
I posted this problem a month or so ago
and you guy's said maybe the problems
was the carb,but try the cheapest first.
So I did I did the plugs,wire and cap
first.That helped very little but it
did help.Next I had the carb rebuilt.
Yesterday was the first nice day in 
while so I install the carb.
The problem is still there,what am I
missing???



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