my 99 crown vic has recently been starting very hard on cold start issues. it takes longer to crank engine over to start, then you have to flutter the gas pedal in order to keep engine running, otherwise, you let off the gas, and it will die. once warmed up, she runs great all day. the only code is the left side cat is going bad. this vehicle is a retired cop car with 130000 miles. thanks jt

 

Maybe the Idle Speed Motor. Sounds like the classic symptom for one starting to fail.

 

Can you advise on how a home mechanic can test the Idle Speed control? Your advice has been extremely helpful to me. How exactly does the ISC work?

 

The ISC controls the amount of air that is allowed to enter the engine to regulate the rpm to allow it to idle when cold. You might be able to use a screwdriver handle and tap on the ISC and see if it helps in the idling. Remember, I said "tap". Below is a generic picture of one. It is located to the rear center of your engine.
Click here

 

Is it influenced by the Coolant temperature sensor or does it sense temp. on its own? Is there a way to clean/lube it? correct me if I'm wrong, but it seems to function like a choke on the older cars. When it senses cold does it cut off some of the air flow?

Thanks!

 

Yes to allof yourabove statements.It is controlled by the ECT sensor and the air tremp sensors.However when cleaning, you need to be careful because therwe are rubber seals and gaskets that do not like cleaning products.

 

Way2old,

Thank you again for your advice! I cleaned it with alcohol and brushes and lubed it with some light oil. No problems whatsoever on start and warm up. I was wondering, how often is it that the solenoid on these actually goes bad (seems like it would be a fairly reliable part) compared to how often they are just dirty and stuck?


Thanks, You're the best

 

Most of the time80%it is just dirt that causes the problem. Very seldom does the little motor go bad. If it does it will give a trouble code. The seal that holds the pintle spring in place will come out and keep the pintle in the closed position. Good luck.