rev up your engines I got a vehicle with a common problem
it's an old Toyota rav4 it's a 97 and when you start it up when it's cold in
the morning it has a tendency of dying out let's keep your foot on the gas well
once it warms off it goes okay so let's start with a real diagnosis I'm
talking something as simple as fog air filter worn spark plugs does it so let's
check that pop this baby check the air filter it looks pretty clean it's not the air
filter let's check some spark plugs wiggle around hard to get off on it
that's doing on a cold engine so you don't break anything
aluminum is pretty soft actually it's an excellent shape it's firing a right
temperature little light color nothing's worn out there's nothing wrong with the
spark so I'll get it back in snug put it back on now of course you want to be
logical check all four spark plugs so I checked them all they all looked exactly
the same so there's nothing wrong with a sparkler now a lot of times when a
vehicle runs poorly when it's cold but okay when it's warmed up it's a weak maf
sensor mass airflow sensor but alas this is an old rav4 it's a
ninety-seven it doesn't have a mass airflow sensor it has a map sensor now
they rarely go bad and on these Toyota's if they do they'll generally trip a code
from the map sensor and there's no code from the map sensor so the next thing to
check for is vacuum links we'll start it up and look for vacuum leaks
no way as you can see it's stalled out cuz when it's cold it's cold outside you
see my jacket on it has a tendency stalling out so we're gonna have to rev
it up a little let it warm up a little 9 check for vacuum leaks well check for
vacuum leaks first listen now I don't hear any vacuum leaks not at all I don't hear
it's sucking air I kind of got it's a vacuum leak and if you do have a vacuum
leak bad enough to make car die when it starts up first thing in the morning
it's gonna show that it's running too lean from socking too much yard so let's
check the data and when we check the data this is live data look at this long
term fuel trim it's actually subtracting 7.8 percent of the fuel if it had a
vacuum leak it would be adding fuel not subtracting because it would have too
much air and not enough fuel this is the opposite so it's not a vacuum leak but I
have noticed there's a code P0114 for the intake air temperature sensor is
ready so let's try a new sensor that could be totally logical and since
it's subtracting fuel maybe the fuel injector is dirty so I'm gonna run some fuel
injector cleaner through it too, so here's the air intake temperature sensor simple
thing right here simple to do just pull it out the sensor is in here it's got a rubber grommet so you got to wiggle it a little out it
comes then plug the new one in here snap the electrical connection on that easy now
I'm gonna put some fuel injector cleaner in the gas tank now any fuel injection
cleaner that has the PEA the nitrogen based cleaner is perfectly fine that's
the only thing that matters Chevron techron has it most of the big
cleaners have PEA in it now realize there are cleaners that don't have it
and that's seafoam I don't advise using seafoam cuz it doesn't have any PEA what
happens is these injectors this they need the nitrogen based cleaner for them
and to clean the valves and a fuel injectors so stick with any of them that
say contain PEA so now the vehicles been sitting all night let's see what
happens this morning when we start it up it starts right up and
no more clunking now now it is a good idea to wait till the next morning you don't
know what's gonna happen when an engine is ice-cold lots of things gonna happen
we figured we have it fixed but you're not gonna know till the next morning
when it's cold and you start it up put it in gear and it doesn't conk out
anymore so now you know how to diagnose and fix a vehicle it stalls out when
it's cold in the morning but runs okay once it's warmed up use your noggin be
logical it's a lot of stuff you can figure out with a few simple tools like
a scan tool and a couple wrenches and a can a fuel injector cleaner, so if you
never want to miss another one of my new car repair videos, remember to ring that bell