Sasnuke

I would probably stop using the injector cleaner going forward...in case it's creating an issue. I know it's a Lexus branded product, but it's best to eliminate any variables.
My key battery is actually low right now as the ca is showing me the message. If you're not getting the message then you're probably ok.

If you're not getting any idling issues, or black smoke out the tailpipe on startup, then you likely don't have an injector issue.
For what it's worth to pull a couple plugs just to see their physical condition, I would do that next.

Any chance that you carry around more than one smart key on your person? Like if you had another vehicle that uses a smart key and you keep a key for it on you with the Lexus key.

sakibmd

Thank you. I think it would be a good idea to stop using those injector cleaners. I will get the spark plugs checked next.
No, in the house mine is the only smart key.

Waffles17

If you restart the car after the cold start, does it also hesitate?

Sasnuke

I think he was referring to this in one of his previous posts. See above in bold.

Waffles17

​​​​​​So the issue is only on old starts?

My bet, fuel pressure. Bad Plugs don't "decide" when to be bad

Sasnuke

Checking the fuel pressure one more time to be absolutely sure isn't a bad idea, but considering that all the parts in the tank have been changed and they have monitored pressures in various conditions, then it's very unlikely it's a fuel issue.
The only other possibility is if there is a loss of pressure from an injector(s) that are not closing properly when the vehicle shuts off.
But then the vehicle would have other symptoms that would overshadow the extended crank...i.e. rough idle after starting, possible stalling too, and black smoke out the tailpipe...both of which were confirmed not to be happening.
Then there is this anomaly of the theft deterrent seemingly having an effect on the condition...which I couldn't even begin to explain why.

And by checking the plugs I'm not really suggesting they are bad, more so fouled...meaning that they are physically capable of firing, but due to buildup on the tips (abnormal buildup), they may struggle to produce a good spark initially when the vehicle is starting, but after a few fires the spark is good enough for the vehicle to start and run properly. It's easy to just pull a couple, or all, the plugs and do a visual inspection.
The theft deterrent thing is still a head-scratcher though.

Waffles17

Hmm, ya won't be a bad idea to check 2 plugs at least.

Are fuel injectors likely to leak on these cars?

At 100k km won't be a bad idea to change plugs if they were not changed already

sakibmd

The lack of experienced mechanics is an annoying problem here in Qatar. Most of the mechanics do guess works. On the other hand the dealerships are bunch of scumbags and they simply do not have good mechanics. All their mechanics are only good for changing oils. Nothing else. Most of the problems on my car I had to point that out myself by doing online research. Now I have only 1 shot before my warranty expires, I will use a Bosch Service center to run some diagnostics on my car before heading out to the dealership. So far according to you guys, I'm going to get the followings checked:

1. Spark Plugs
2. Fuel Pressure

Moreover, I will run a bumper-to-bumper check to see if there is anything else that I can get fixed by the warranty. Is there anything else you guys suggest I should check? Any other specifics on the fuel delivery system? or the injectors?

Please let me know.

Thanks you!

Sasnuke

The likelihood of an injector leaking is very slim, but nothing is impossible...it's just not a known issue.
I think I did read some posts about the early 3IS having some injector issues, but the symptoms were well beyond an extended crank...like it was blatantly obvious.

Waffles17

Exactly. U would probably have a fuel smell, higher fuel consumption, the short term fuel trim would be higher, probably black smoke, and so on.

Let's rule out the plugs first, as it's the easiest. Also check the gaps for the plugs while at it. Wrong gaps can do wonders

sakibmd

I just disconnected the battery for 15 mins and connected it again. Then I started the car. Few moments later I had a very mild vibrations at the idle. Then I took the car for a test drive and the idle seems to have gone away. I will check again when I drive to work tomorrow and observe.

is that mild vibration at 600rpm normal? The vibration I felt was on the seat and on the steering wheel. It was an one off thing. The car usually idles around 800rpm

Sasnuke

It could have occurred because the battery was disconnected. If it doesn't do it again I wouldn't worry.

Have you checked the condition of the throttle body? The carbon buildup around the throttle flap.

bob123

I wouldn't be concerned with any abnormalities after starting engine soon after the battery was disconnected.
The one and hopefully last time I disconnected the battery for throttle body cleaning, my engine started, but stopped soon after. Then it restarted without issues.

I like the idea of pulling a spark plug or two and check condition.

V00D001

There was a recall earlier this year from Toyota/Lexus on certain model fuel pumps. Your car isn't on the list, but if the replacement fuel pump corresponds to a "recalled" pump, you may still have a bad pump. The symptoms you're having don't really correspond with the issues with those bad fuel pumps but I would still check with your service department and make sure the replacement pump that was installed isn't on that recall list - just to rule it out.

NickCaesar

my 350 when cold starting vibrates quite a bit. You really feel it in the steering wheel and seat. Goes away once it warms up a bit.