Hey guys I have a 2008 MT base model. Sometimes when I start up the car it will start up for the first couple seconds, then the RPM will drop, car will shudder a little bit and turn off. This only happens AFTER the car is warmed up, never on a cold start. Sometimes this also happens when I am driving and come to a stop. The RPMs will drop, car will shudder and turn off. Any ideas on what could be wrong?

If I try to start it up by giving it some gas then it is fine.

Any help is much appreciated

 

Have you hooked it up to a scan tool? Not all codes will trigger a CEL.

 

No not yet, I do not have any immediate access to one. I also do not have a CEL on. Just trying to see if I can get a very general idea of what may be the issue

 

I've been having the same problem with my '03. I've been researching it for a few weeks. Lets see... The first thing I came across was a thread of a couple of people saying to just leave the problem alone, and it'll fix itself(the ECU needs to adjust/relearn idle after air filter changes, battery changes etc) within a couple of days or weeks of normal driving.
https://my350z.com/forum/maintenance...rt-stalls.html
Of course that's not the case for everyone, so some people have mentioned doing the three (accelerator pedal release position, throttle valve closed position, and mainly idle air volume) relearn procedures found here: https://my350z.com/forum/maintenance...procedure.html emphasis on exact times, or the relearns wont initiate.
Only other solution I've seen is cleaning both the MAF sensor (I did this. The car has a better pull and smoother acceleration... But did not fix the warm-start stalling problem), and the throttle body. I've yet to clean the throttle body cuz I'm hesitant of the consequences I've read here. If u manually move the butterfly, the idle will be thrown off, and the car will idle high(1200-1500ish) since they're "drive-by-wire"(computer controlled). A remanufactured TB would cost around $130ish. A few people have said it's totally okay as long as u disconnect the battery before cleaning, and then do the relearn procedures after ur done. Some have even said u don't need to do the relearns. If u go this route, the most common cleaners I've seen suggested are the CRC TB/intake cleaner, and MAF cleaner... But yea, that's all the info I've gotten so far. Hope it helps.

 

Clean the TB to start and do the idle air volume relearn procedure as above, and see if it improves.

 

Thank you guys for all your input, will try these methods out

 

NP. Update us with how it goes

 

I would almost suggest you just remove the TB to clean on this platform, it's simple to remove and hard to get them really clean on the engine anyway. You can't open the throttle blade with the engine off using the gas pedal on this platform, so rather than advise people who may not know how to be careful when opening it manually, it's safer to remove, clean and re-install.

Any good brake cleaner or similar spray will work just fine to clean the gunk, all of those cleaners have acetone as the primary detergent, so they all pretty much work the same. Stay away from any metal bristle brushes to clean the bore, use plastic if available, or brass if that's all you can get.

Start the car one time before you do the re-learn to suck any chemicals through, which can lead to a false high-idle condition due to the added fuel. Run it for a couple min and then do the re-learn. Very simple.

 

This happened to me before and I found out it was the going out fuel pump! So just replaced the whole unit and no more low idle and shudder!!!

 

People clean the TB while its still on the engine? O.o wtf? Lol
I cleaned the TB, MAF sensor, and replaced the hose that connects under the intake tube(I discovered it was cracked while removing the TB). Everything running good and smooth

 

Mis-typed, meant to say ignition on. Usually you are supposed to turn the key on and push the gas pedal down to open an electronic throttle for cleaning. On the Z it will not move with the engine off, so you can't avoid opening it manually.

Glad you got the issue solved, leaks after the MAF will do that to you.