IS200 Codes and misfiring

[LS03]

Hi,
I'm a female so I'm not too up on mechanics.

My IS200 starts off fine without trouble. Within 20 minutes or so of driving the car suddenly fire on five cylinders. The engine management light comes on.

If I leave the car off for about an hour to two hours or so it will drive fine again. Then after 20 mins it will start misfiring again.
So it seems something heats up, and that's casuing the problem.
This has gotten worse over a couple of months. It used to happen less. Now it's everytime I go out.

Codes are PO171 and PO303.
An odd time I get the code PO300 but not generally.

I changed all the plugs, and the coil on the third cylinder. Nothing changed with the problem except it ran a bit smoother.

Thanks for any help. Appreciated!

[ColinBarber]

Given the plugs and coil pack has been replaced then I would assume it is a fuel injector not working correctly as it gets hot. Injector three would make most sense to investigate - either move to another cylinder or test/replace. The P0300 random misfire is common for a fuel injector problem as the ECU doesn't always detect the correct cylinder. P0171, too lean, also makes sense if the injector isn't firing correctly.

If you move the injectors you will need new o-rings to seal them. At that age the old ones will definitely leak if you try and reuse them.

[rich1068]

5 hours ago, LS03 said:

Hi,
I'm a female so I'm not too up on mechanics.

I'm male and I'm clueless. Welcome to the forum.

[LS03]

@ColinBarber,

Thank you for your advice.

I'll change the injector on the third cylinder and I'll come back here to post after I test it out.

Really appreciated!

[LS03]

On 5/16/2018 at 8:25 AM, rich1068 said:

I'm male and I'm clueless. Welcome to the forum.

Thanks! I'm glad to see i'm not the only clueless one.

[LS03]

On 5/16/2018 at 8:09 AM, ColinBarber said:

Given the plugs and coil pack has been replaced then I would assume it is a fuel injector not working correctly as it gets hot. Injector three would make most sense to investigate - either move to another cylinder or test/replace. The P0300 random misfire is common for a fuel injector problem as the ECU doesn't always detect the correct cylinder. P0171, too lean, also makes sense if the injector isn't firing correctly.

If you move the injectors you will need new o-rings to seal them. At that age the old ones will definitely leak if you try and reuse them.

Colin,

I put a new injector in the third cyinder and it's fixed the problem!

Had trouble getting the rail off as the throttle body was in the way of one of the bolts. Got that off though eventually. Definitely a man's job - they are more dexterous. No wonder women aren't mechanics! Not cut out for it.

Thanks so much for your help. Really really appreciate it!