Hi everyone, I bought a 2002 SC 430 a few months ago. About a month or two after I purchased the car I started experiencing hesitation. Usually, while I'm driving at higher speeds, I feel the car loses power for a second or two. The problem got worse in the later weeks as the car would completely stall out while I'm driving, luckily it only happens on the sidestreets.

When the car stalls, the engine light, and the VSC light goes on. I would need to re-start the car to continue driving.

I've taken it to two mechanics so far.

Steve's auto in Northridge could not fix the problem. They re-set the codes but could not diagnose the origin of the problem. Automotive Instincts also in Northridge ran a better diagnosis. They traced the codes to the Mass airflow sensor. They replaced it, and kept the car to drive and ran the diagnostic several times to ensure the codes do not comeback.

It worked well for about a month, but unfortunately one night on my way to the beach I experienced the hesitation on the freeway at high speeds. Luckily the car did not stall until I hit traffic and was able to re-start the car. The same issues, hesitation, stalling, engine and vsc light goes on.

the previous owner did install a S-AFC II Airflow converter which I do not turn on. I am not sure if this is the culprit. I've asked the same question to my mechanics, but both do not have experience in aftermarket parts.

I am not mechanically inclined.

Questions for the group:
What do you think is the issue?
Can you recommend a mechanic n the Los Angeles area. I live in Granada Hills.

Thanks

 

If it were me, I would get rid of the aftermarket device and hope it would correct the issue.

 

If this is what you have, then yes, it sounds like it is causing the problem you describe.
https://www.nolimitmotorsport.com/ap...criptions.html

 

I agree, you (like me) sound like a person who likes the reliability of the OEM design and parts.

Taking out the Aftermarket computer and putting in original equipment will solve your problem.

 

Second to Daryl and BGW.

 

First off, I agree with the advice that has been given, take off the aftermarket device and find out if that resolves the problem. Way back when I had semi similar problem where out of the blue, once a year or so, our SC would stall and then not start. Not exactly like your situation, but here is the thread as an FYI:

https://www.clublexus.com/forums/sc4...down-help.html

 

Yes that is exactly what I have. Thanks for validating my suspicions.