Hi Experts,

I need your help to identify the issue with my Buick regal '99 LS (74k miles). I was driving this car for almost 2 years no major issues received.

But suddenly from the last month it’* giving trouble frequently. Engine runs great but suddenly dies/stops while driving at various speeds. Turn key to restart after stop but nothing happens.

Engine is very smooth with no hiccups then out of nowhere it happens again and has been more frequent. I have left my car AAA service center but they unable to identify the issue and leave my vehicle with my always. This issue happens whenever I come back from shopping at night. In the next morning AAA service person start the vehicle its start with no issues. They checked for error codes per technical manual but get nothing. There is no hesitation or any warning that engine is about to stop.

I replaced crank shaft censor and many things which they suggested but my problem is i cant have confident on the car so that i can drive long. Please suggest me

Appreciate your response.

When you say nothing happens when you try to restart do you have power to the insterment panel and lights or is everything dead? Or does the starter crank but the engine not fire? It sounds to me like a ground is loose or the battery has a bad connection between the two positive cables. If it is cranking and not starting I would suspect the ignition control module is going out when the engine gets warm.

Yes, It does has the power since the starter crank but engine is not firing.

Battery loose connection + ground connections are verified by the Service mechanic. There is no issues with that.

Ignition control Module may be cause since I live in AZ, how to rectify that? How to check when there is a next failure ?

The ICM is a hard thing to diagnose because of how intermittent they act up. I've seen where some people will start the car and use a heat gun to warm up the ICM to try and get it to quit working.

if the ICM is bad, when its hot and not starting you wont have spark, or very minimal spark. take a plug out and lay it somewhere in contact with a good ground and see. just dont touch it or you will get zapped

Where i can find the ICM ? any help will be appreciated.

flat thing the three coil packs are attached to, you just take the little bolts out of the coils and they lift up and the icm is under that. if you replace it get some dielectric grease for the coil terminals and make sure you use the heat sink compound they give you between the coils and ICM