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Junior Charter Member
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876 Posts
Discussion Starter · #1 ·
The car runs great when driving but when you stop at a light it coughs and idles at about 400rpm and almost stalls for about 5 seconds then returns to normal idle about 850rpm.

The car ran great on the weekend and just started doing this today.

Its a stock '89 5.0 converted to Carb with electric fuel pump and an Aod Tranny.

Sofar I reset the timing and float levels, they were real close, and I replaced a torne vaccume cap. fuel pressure is good and it starts fairly easy when warm.

I can't imagine what it is I'm missing?
 

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Premium Member
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365 Posts
Sounds like vacumm leak or fuel flood out to me. Put your hand over the carb and try to choke it off ( completly covering all of the air horn). If the motor increaces in speed, Vacum leak.... If you can choke it off till it dies, chances are no leak.
May be a float that is sticking, bad needle valve in the carb sticking, letting the carb flood out, flooding the motor untill the fuel level goes down in the float bowl, then recovering to the normal idle.

When it starts to die again, tap the float bowls with a wooden hammer handle and see if it clears up faster. Another check would be twhen it starts to die, to have a screw driver ready to take the float bowl fuel level screws out. If fuel is rushing out of the level check holes, it is flooding out.. Time to get the float level strightend out.

Just my .02

Jerry
 

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FFCobra Craftsman
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1,767 Posts
Sounds like a vacuum leak to me also....
 

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FFCobra Fanatic
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192 Posts
Vacuum leak or the float might be set too high.

Is it worst if you come to a hard stop rather a slow stop?
 

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Junior Charter Member
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876 Posts
Discussion Starter · #6 ·
thanks again guys, as always your right on top of things.

So after hearing the suggestions about a vaccume leak, and because it's getting dark and I don't want to take the carb apart tonight I thought, what if the problem that was the problem that I think is nolonger the problem is actually still the problem and I only think that the previous problem is now a new and unrelated problem.

So I returned to the previously torn vaccume cap, which I had replaced, and checked all of the vaccume lines and caps. the problem was...

the replacement vaccume cap was too big!

smaller vaccume cap and the problems gone

Only question is why do my vaccume caps fall apart? could fuel be getting in there and making them rot? Ohwell the car's fixed for $3 I can't complain

Thanks again guys!
 

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Junior Charter Member
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26 Posts
Sounds like fuel "slosh over". Try adjusting the floats SLIGHTLY lower.
 
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