Rough idle

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05-17-2016, 05:13 PM

#41

Paulywog

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Quote:

Originally Posted by Nocturnal1

With my rough idle, it didn't throw a code and I couldn't remember exactly what the difference is in RPM's, but it was probably less than 100 RPM. Your idle RPMs will vary due to different conditions of the engine (temperature, air conditioning, etc.). Is your problem rough idle or surging RPMs? You might mention the brake booster vacuum hose connection at the intake manifold to your mechanic.

Yes Surging probally describes it better. Normally at like 5-600 rpms while idling and then it drops down to about 3-400 rpms. And it's not constant more so when it's warmed up and running. And not every time

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05-18-2016, 02:31 AM

#42

Nocturnal1

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Quote:

Originally Posted by Paulywog

My idle RPMs is about 590-620 when the engine is at normal operating temperature (warmed up) with air conditioning off and transmission in drive. If your RPMs fall to 3-400, it sounds like there is some problem even though you don't have a code. I'm amazed the engine doesn't die at those low RPMs.

If possible, note the vehicle & engine conditions (for example, air conditioning on or off) when the RPMs drop and advise your mechanic. You may want to consider brining your vehicle to a mechanic that is more familiar with Fords or F-150s.