Jim Grant's Tech Tips
'98 Ford Ranger, Intake Whistles and Moans
Q:
When the temperature
is above 75-80 deg and when my '98 Ford Ranger (4 liter V6) has been driven
20-25 miles it has a whistle/moan at idle. I've taken the intake duct
hose off from the filter at idle and the noise is decidedly louder and
coming from inside the intake manifold. It does not have this resonance
at lower temperatures or other than idle. The sound is loud enough that
other drivers will turn and look at a traffic light. Any ideas for a solution?
A:
I would suggest removing
the intake duct hose from the intake manifold and inspect the throttle
plate. Why? It is common for carbon deposits to build-up on the throttle
plate and idle air control valve. The build-up of these carbon formations
can create some interesting problems. Ford claims that their throttle
plates have been treated with a special coating that prevents carbon build-up
problems and no cleaning is necessary. What they claim and the reality
of the real world just doesnt match up. If inspection finds that
there is carbon build-up use a mild cleaner on a rag and wipe away at
the throttle plate and bore, until the carbon build-up is removed and
all is bright and clean. It is possible you have a vacuum leak that is
causing the whistle, but those carbon deposits on the throttle plates
are a common problem.
|