I have an idle question on my 92 Ford Aerostar 3.0L auto trans. When the vehicle is cold it starts and and idles normally but dies when I put it into gear. The only way it will start again is to push the accelerator to the floor and crank the starter for a minute and give it gas too keep it running once it starts. Idle seems to stabilize in park but engine dies when I try to put it in gear again. after about 10 minutes of this it will idle in gear OK and runs normally. After it cools off - same problem again. Any advice greatly appreciated

 

Common problem on these older engines, can have several causes:

1. Dirty/sticking Idle Air Control (IAC) valve. Easy to get to and remove for cleaning/testing. Do search on same acronym for more details.

2. Loose/broken vacuum line. Check the vacuum "tree" on the top rear area of engine (need to remove inside access cover) and see if all the tree ports have either a vacuum line securely attached or a plug on the vacant 'limbs'. From there, look in the engine compartment, for the smaller, off-white colored vacuum lines along the passenger side, above the HVAC blower. These become brittle with age and any maintenance in that area inevitably will lead to breakage.

3. The Mass Air Flow (MAF) sensor located between the airfilter box and the start of the air tunnel. Even tiny amounts of dust specks or contamination on the fine, heated wires
on this sensor will cause fits with engine performance. It can usually be CAREFULLY removed and cleaned with judicious application of electronics spray cleaner. Do not attempt to touch the wires with anything, they are extremely delicate. Again, a search for MAF for additional info.

That fact that once warmed up, the engine operates correctly would tend to remove a vacuum line problem or MAF from consideration. Problems with either of these would be a persistant problem, whether cold or hot engine.

You can also pull malfunction codes easily with your model. Look for a sticky note at the beginning of the Aerostar forum for "Pulling codes". You can do this with a paper clip and these instructions. Try to pull the codes and report your findings here.

 

think it may be the ECT engine coolant temp sensor. about the only sensor beside the ACT air intake temp sensor that is active during cold start, cold run.

one other member had a similar reported problem recently with a defective failed ECT.

Ford Fuel Injection Engine Coolant Temperature Sensor (ECT)

 

think it may be the ECT engine coolant temp sensor. about the only sensor beside the ACT air intake temp sensor that is active during cold start, cold run.

one other member had a similar reported problem recently with a defective failed ECT.

measure resistance with wires disconnected when cold. should be greater than 30k ohms

Ford Fuel Injection Engine Coolant Temperature Sensor (ECT)

 

Hello!! I'm the other member...... In fact I have fixed the problem this afternoon: stalling when cold was not my major problem but I have found that IAC connector contacts were "loosy"; after retensionning it work perfect, even with A/C on.
My problem with ECT... was not a problem... pins seemed clean but my ohmmeter gave me zero ohms!!! I was puzzled, but after cleaning pins with an hear tip with steel wool the value was good. After cleaning and retensionning ALL the sensors and connectors that's seems OK.