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I am hopefull LOC can come to the rescue before I pull out the last remaining strands of hair. :question:

Cranking & idling GS300 - I have a problem ... difficult to paint but here is the picture

1. Starting from completely cold .. Fine, although always needs to turn over several times before firing ...

2. But when starting if engine warm (any degree from 1st guage marker to full ) takes much bigger crank to start, then very rough, coughs and splutters to life, revs start and stay immediatly low - hunting - almost stalls - after pulling away give it some gas and it revs but doesn't speed up, and will cough & choke - quiet backfire sometimes - no acceleration. - stop at the lights and it occasionally even stalls.

After 5 minutes it settles down and is fine from then on.

Lexus Twickers have looked at it twice - The first time (During full service) they cleaned out the throttle body - no improvement. They also stated no errors thrown up by the ECU.

Second time - they ran it cold , then hot - got someone else to check it - reported "Running fine, no problem, runs well'

Clearly they didn't really test it properly as this is happening all the time - not just occasionally and it is impossible to know how they missed it unless they simply started it, ran it untill hot and tried re-starting just once without waiting for half an hour. (Although today I was out and about, stopping off at shops etc every 10 minutes and everytime I re-satrted I had same problem.

Has anyone else experienced this problem? or can give some advice (Preferably not including lexus mechanics!) - already paid over £100 for no improvement)

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Sorry I can't offer any help,

But Colin Barbar would be the chap to ask, perhaps drop him a PM or i'm sure he will be along to answer soon.

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This sounds something like a fuel mixture problem - possibly to do with the auto-choke, I'm wondering if the auto-choke is kicking all the time rather than just when cold.

Has the fuel usage increased a bit, it may not be much - say 50 miles less to a tank. I don't think this type of problem would show up on an ECU Diag.

Hope this helps

BR

Paul

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Have no knowledge of the GS, but if the plugs and plug leads are Ok,based on

other fuel injected cars(is it?) I would have the fuel line pressure checked.

It may be worth checking the distributor cap for tracking also.

Worth a try if stuck!!

cheers

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yep goto agree with paul on this, sounds like a cold start device problem, check the vacume lines around the throttle/inlet manifold, ensure they are all connected and not split/perished

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Yep, I agree too.

There are alot of vacuum lines on these, what with the EGR control and that. Make sure they are ok, and none blocked. If the engine management isn't finding owt then it's most likely a mechanical failure like that. The engine management can only report on the findings it gets from various sensors. And bear in mind, it doesn't always mean the sensors are reporting the correct findings, which would also make the ECU think everything was ok.

Suppose it could be a sticky injector or something like that too.

Blimey, there's too many things! Where do you start!!

I'd say look for the obvious first, as said before.

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Lots of thanks for the pointers

It's an enfuriating problem - I will post the outcome.

1st - check those vacuum hoses ...

(PS - would it be worth re-setting the ECU anyway?)

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Lots of thanks for the pointers

It's an enfuriating problem - I will post the outcome.

1st - check those vacuum hoses ...

(PS - would it be worth re-setting the ECU anyway?)

I'd personally wait until you have the problem resolved, resetting the ECU would give better performance but would only make the problem a bit more difficult to cure. Once you have fixed the problem, then reset the ECU.

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On other makes I've seen this type of problem due to either

a ) fuel lines getting warm.

b ) dirt in fuel cap vent preventing air getting into the tank so that a vacuum builds up which reduces the flow of fuel to the engine.

I don't know if either of these problems can occur on the Lexus though. I notice that when I remove the cap on my IS200 there's sometimes quite a strong vacuum in the tank, but this doesn't seem to affect the engine at all.

Tony

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