Need help - Rough idle when starting hot - TCCoA Forums
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post #1 of 6 (permalink) Old 12-20-2017, 12:57 PM Thread Starter
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Need help - Rough idle when starting hot

Hi guys,
Recently, whenever I start up the car with a warm/hot engine I have been experiencing a rough idle (RPMs too low) for the first 30 seconds or so accompanied by what i think is fuel odor and some smoke. It goes away when I put it in gear and drive off. What could it be?

Apparently the previous owner had the IAC, MAF and crank position sensor replaced not long ago. I was reading up on the forum about it and one guy was suggesting to replace the Engine Coolant Temp sensor in a similar case. I'm not sure if that is relevant to my symptoms? I intend to replace the fuel filter for unrelated reasons this weekend, so that might help a little, but I don't think that's the cause.

Any help/advice would be appreciated.


Last edited by roborated; 12-20-2017 at 01:11 PM.
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post #2 of 6 (permalink) Old 12-20-2017, 01:26 PM Thread Starter
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I found this thread on the Explorer forum which lists an identical problem: Intermittent rough idle on warm start.... | Ford Explorer and Ford Ranger Forums - Serious Explorations

Those guys seem to think it might be down to the throttle position sensor or dirty fuel injectors. Any thoughts?
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post #3 of 6 (permalink) Old 12-20-2017, 07:47 PM
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I'm not sure if you have a throttle position sensor on your later model but a voltage check on it and all the other sensors you mentioned might fix your issue.

There are instructional threads that can be dug up here with searches.

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post #4 of 6 (permalink) Old 12-21-2017, 03:07 PM Thread Starter
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@gordonm1 Thanks for the suggestion! I think the explorers they were talking about on that forum were around the 1995 model year as well so I assume the T-Birds would have them too. I'll go look for those threads.
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post #5 of 6 (permalink) Old 01-15-2018, 12:38 PM
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Try cleaning out the IAC, though it would most likely show up when the engine is cold with a rough idle.

I replaced my fuel injectors a while back and it made a world of difference. It was worth it too. I found a set on Ebay, new for $80. It was cheaper to replace the injectors than have an injector flush done by a shop.

You could try running some SeaFoam through the throttle body, crankshaft and gas tank as well. Due to the ethanol in the gas during the winter, engines tend to run like crap. Though, I think they put in year round now... ?

My two cents.

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I've had too many other cars to mention...
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post #6 of 6 (permalink) Old 01-15-2018, 03:28 PM
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Yes, a minimum of 10% ethanol is everywhere, all year - been that way for years.

Most areas have random stations with "ethanol free" pumps that are clearly marked. Also clearly marked with up to a 25% higher price.


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Previous Fords:
95 T-Bird LX 4.6 - fully optioned, owned 15 years, 220k miles
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