96 merc.tracer 1.9

our car started running bad,ive done the normal maint.gas
filter,plugs.wires,air filter etc.car starts fine but begins to idle up
sometimes 2-3thous.rpmthen down below 700 rpm then pulsates up and down
sometimes even stalls,when driving it seems fine until comes to a stop
rpms stay high around 1500 then drops like mentioned before i installed
a new idle air valve and trotle position senser it still doing it also
had local parts store scan codes because the engine light is on they
came up with the mass air flow sensor as the problem but i not sure if
thats it either any help or direction would be appreciated

I guess iff the engine codes says that's what it is then that's what you
should get checked, however if that's not the problem it might be the
Ignition Control Module which you can get tested for free at some auto
parts sotres. As for the air flow sensor, someone posted on our local
newsgroup that he removed a hair from his and his problem went away.

" ) writes:
> our car started running bad,ive done the normal maint.gas
> filter,plugs.wires,air filter etc.car starts fine but begins to idle up
> sometimes 2-3thous.rpmthen down below 700 rpm then pulsates up and down
> sometimes even stalls,when driving it seems fine until comes to a stop
> rpms stay high around 1500 then drops like mentioned before i installed
> a new idle air valve and trotle position senser it still doing it also
> had local parts store scan codes because the engine light is on they
> came up with the mass air flow sensor as the problem but i not sure if
> thats it either any help or direction would be appreciated
>


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wrote:
> our car started running bad,ive done the normal maint.gas
> filter,plugs.wires,air filter etc.car starts fine but begins to idle up
> sometimes 2-3thous.rpmthen down below 700 rpm then pulsates up and down
> sometimes even stalls,when driving it seems fine until comes to a stop
> rpms stay high around 1500 then drops like mentioned before i installed
> a new idle air valve and trotle position senser it still doing it also
> had local parts store scan codes because the engine light is on they
> came up with the mass air flow sensor as the problem but i not sure if
> thats it either any help or direction would be appreciated

You need to post the actual trouble code that was stored in your ECM
for more accurate help. There are a few MAF specific OBDII codes, but
there are also "too rich" and "too lean" codes that are often caused by
a dirty MAF sensor on Fords, which don't directly condemn the sensor by
definition. BTW, the sensor "wires" inside can be easily cleaned if
need be.

Regarding the idle/stalling, I would look for a large vacuum leak,
especially the PCV valve hose on top of the 1.9 engine. They can burn
through or get soft and randomly flex at the failure point to cause
high idle -or- stalling on decel. The "MAF code" may just be "P0171
system too lean" from a large vacuum leak.

Toyota MDT in MO

where is the icm located on the 96 merc.tracer,& how to check if the
idle air control valve is good or even working, thanks for ealier
response.

this is a followup if anyone cares ,seems the problem was a large
vacuum leak the intake gasket failed to do its job detiriorated so the
post on large leak was good

wrote:
> this is a followup if anyone cares ,seems the problem was a large
> vacuum leak the intake gasket failed to do its job detiriorated so the
> post on large leak was good

Thanks for the followup. Yes, people appreciate the courtesy, esp. in
the case of future searches on this topic.

BTW, if you haven't replaced the intake manifold gasket yet, you may
want to consider replacing the cam position sensor at the same time,
since it's removal is blocked by the manifold. It can fail and cause
stalling/no starts, and the part is only about $20 in the aftermarket.
It is the black plastic sensor that is installed in the head towards
the back of the car and near #4 cylinder. The pole piece that goes
into the head is about 3" long, that is why it won't come out without
intake manifold removal.

Toyota MDT in MO