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Cold start hesitation

My vehicle hesitates on cold starts and once it’s cranks over it idles fine. No loss off noticable power or anything, it didn’t even have a check engine light until just today. (Check engine light on) Anybody know what I might be looking to repair. I haven’t run a code yet, I will as soon as I can.

Cold temperatures stress the ignition system, the air/fuel mixture control system, and the idle air control system. Hard to say what exactly the problem is w/o your shop doing some testing. I’m guessing you’'ll find as one part of the solution, you need to replace your spark plugs.

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I agree, something with the air mixture, as long as the engine hasn’t been off for too long, it starts right up.

Try this the next time the engine has been off for a while.

Turn the ignition switch on so the dash lights come on for two seconds, and then turn the ignition switch off.

Repeat this a half dozen times and then try starting the engine.

If the engine starts right up, there’s a problem with the anti drain-back valve on the fuel pump assembly.


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No experience w/your engine, but on my 90’s Corolla there’s a gadget that measures the engine coolant temperature and uses that to adjust how long to fire the fifth injector – the so called cold-start injector. Nothing has ever gone wrong with all that, so never had to fix it. On newer engine designs there’s no cold start injector. Instead the computer measures the coolant temperature using the ECTS and injects extra gas through the normal injectors. So you could have a problem with the ECTS or , less likely, the computer or the injectors. Make sure the ignition system is working flawlessly first, before considering the fuel system. A fuel pressure test would verify that anti-drain back problem Tester mentions above.

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