2000 Ford Ranger vacumn leak rough idle

HARLAN68

MEMBER
2000 FORD RANGER
4 CYL
2WD
MANUAL
18,600 MILES

I bought my truck new, and it runs like a top after I take off out on the highway and still gets about 27-28 mpg. Its idle is real rough, but smooths out when I rev the engine. Recently check engine light came on and took it to Auto Zone and they put code reader on it and it came up as a vacumn leak code he said. He reset it and it hasn't came back on since, but it still idles the same but runs great out at speed. Please help. Thanks in advance. Harlan

Saturday, March 28th, 2009 AT 6:39 PM

1 Reply

MERLIN2021

MECHANIC
17,250 POSTS

You may have a vacuum leak, get a can of spray throttle body cleaner, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody.
Like to know what the code was. If P0455 or 456 it, s not a vacuum leak, it's an EVAP code, and can mean a bad gas cap.

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Saturday, March 28th, 2009 AT 6:53 PM