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My 75 will backfire and bog down after starting when cold. After warming up it runs good. I replaced the thermo sensor and swapped afm's but still get same results!
Could it be the air regulator is malfunctioning ? HELP!
 

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My 78 is doing the same thing; won't replace afm if it doesn't help. Have been told air boot may be cracked. Shouldn't be heat sensitive though. Need help also.
 

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Bill wrote:
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My 78 is doing the same thing; won't replace afm if it doesn't help. Have been told air boot may be cracked.
Shouldn't be heat sensitive though. Need help also.

I would not think the Air Flow Metter would cause that kind of a problem, problems associated with Mass Airflow Metters I have seen have mainly been Z's that will have the idle stick. It sounds like the car is starting so the Cold Start Injector should be fine, how is your vacum? It could be a vacum leak that is sealing up as it warms up. I had a problem similiar and it turned out to be a leaky intake manifold gasket ( NOT FUN TO CHANGE BY THE WAY ON MY ZX ). Take a water bottle ( Something like a sports bottle ). Start the car up, when it is idling ( and still cold ), spray some watter around the edge of the intake manifold were it meets the head, make sure to put a thick layer in the cracks, if you hear your idle steady out, thats where it is leaking, the other place that is notorious for this is the injector seals, you can also spay some watter into the little openings where the tip of the injector goes into the head, again if the idle goes up, then you have a leak, otherwise get out a vacume gauge and see what your vacum is reading. Anyone else out there have something I have not thought of?

Scott Milella
 

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Hi Scott, i have a queation for you, please.. Refer to the question that you reply above, should i or we use carb. cleaner instead of the water to detect the leak? IF the idle is high, than i will try to use the water to seal the leak. On the other hane, if the idle is rough, i will use the carb. cleaner. Am i on the right track? Plaese adv. thanks.
 

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I would not use carb cleaner, as it would be A: more expensive, and B:, it will not flow into the cracks as well as water would. Water is not going to hurt anything in that area. Its what most auto-shops use that I have seen, a little bottle similar to a sports bottle that puts out a nice stream of watter about 1/4 of an inch thick and you spray it, if you want, wipe up the excess afterwards, otherwise you are not going to hurt anything.

Scott Milella
 
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