Idle after a long drive

[BTERRY29]

After a long drive, let's say 50 miles, my car struggles to idle well. The idle gets lopy and I have to feather it in stop and go to keep it from dying. Shorter outings it runs perfect, even at full operating temp. Todays temp outside hovered around 90. Car ran between 150 and 160 the entire time. Even when exhibiting these symptoms.

[chrs1961815]

It almost seems like it could be vapor lock or maybe a condenser.

[nkaminar]

After the engine has been well warmed up the idle setting will change. Try adjusting the idle mixture after your 50 miles. If that does not help then there is something else wrong as Chrs suggested such as an ignition component getting too hot.

[rfitzpatrick]

Originally Posted by nkaminar

After the engine has been well warmed up the idle setting will change.

Well I'll be darn! Thanks!!

[nkaminar]

If adjusting the idle does not help try putting some ice on the coil or change out the condensor.

[shew01]

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Originally Posted by nkaminar

If adjusting the idle does not help try putting some ice on the coil or change out the condensor.

I was thinking about the coil too. It it gets very warm to the touch after 50 miles, the coil may be going bad. A really hot coil can give some interesting behavior.


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[BTERRY29]

Thank you all for the feedback. I’ll keep tinkering and report back

[rocket1]

Originally Posted by bterry29

after a long drive, let's say 50 miles, my car struggles to idle well. The idle gets lopy and i have to feather it in stop and go to keep it from dying. Shorter outings it runs perfect, even at full operating temp. Todays temp outside hovered around 90. Car ran between 150 and 160 the entire time. Even when exhibiting these symptoms.

i have the same problem coming back from a show on sunday (100 miles)the car started popping through the carb and would not idle well.the outside temp was in the 90's and the radiator thermometer showed hot but not overheating.we stopped for dinner and i opened the hood and saw that the "b: Carb was leaking gas from the throat (choke area) i felt the carb bowl and it was plenty hot i think the gas was boiling.after dinner continued home with no problem except idle still was not smooth,have to investigate that yet.

[rocket1]

Originally Posted by bterry29

after a long drive, let's say 50 miles, my car struggles to idle well. The idle gets lopy and i have to feather it in stop and go to keep it from dying. Shorter outings it runs perfect, even at full operating temp. Todays temp outside hovered around 90. Car ran between 150 and 160 the entire time. Even when exhibiting these symptoms.

during that long drive does it backfire or pop through the carb? You possibly do not have the valve lash adjusted properly as the valves and lifters get hot the clearance lessons and if a valve or two don't close all the way you won't get a good idle to the engine cools down.