Hi,
I have trouble starting my 94' SC400. It hapends only when engine is warm. Let say when I park for about 15-30 minutes and try to start engine again, it's starts, but on very slow speed, it's very "shaky" and eventually stops after running for about 10 seconds. I have to try starting like 5-10 times, after eventually starts OK.
Lately I noticed interesting thing...when the engine is warm and when I press the accelerator pedal just a little bit, it starts with no problem from the first "kick". I have no idea what's wrong. One of the sensors? But which one?
Maybe somebody had this kind of problem before and can tell me what's wrong. I don't want to go to "rip-off" dealer, unless I absolutely have to.
Pinio
Oh, I forgot to mention that if engine is cold (eg. after overnight park) everything is OK.

 

First I think you can safely rule out any problems with the battery since you are cranking every time and there is sparkage. Assuming you have high mileage in your SC, here's a list of things you can check out (in order of difficulty/importance):

1) Check air filter (replace if dirty).
2) Add fuel injector cleaner fluid to the fuel tank (a $5-$6 bottle you can get from Wal-mart or any auto parts store).
3) Open up all the tubings connecting from the air box to the throttle body, and use a carb/choke/throttle cleaner to clean inside the throttle body (here's a how-to thread for a 1st-gen SC).
4) Replace spark plugs if necessary (plugs should be changed every 60K).

If you still encounter the engine start-up problem after following any or all of the items mentioned above, it could possibly be something more critical internal to the car, such as a bad idle air control motor or EGR valve. This may not be the case for you, but I wouldn't rule it out. Consider all the possibilities, and start with the easy ones (1-4). Good luck

 

Actually milage it's not very high, arround 100k miles.
Why I said valve? Cause friend of mine has Toyota Camry and he said his case was exactly the same. Happened to be the problem with EGR valve. Is it any way to check it without connecting the computer terminal at the dealership?

 

Well this is where my level of expertise in maintenance comes to a slight halt; I can only go so far as diagnosing the problem

Send a PM to VVT-i; he's the moderator of the Maintenance forum and is a certified Lexus technician.